Praise be to Allaah.
Firstly: purification of the sick person
1. The sick person has the same obligations as a healthy person with regard to purification with water from minor and major impurity, so he should do wudoo’ in the case of minor impurity and ghusl in the case of major impurity.
2. Before doing wudoo', it is essential to clean oneself with water (istinja’) or with stones or whatever takes their place, after urinating or defecating.
When cleaning oneself with stones, it is essential to use three clean stones. It is not permissible to clean oneself with dung, bones or food, or anything that is respectable. The best is to clean oneself with stones and the like, such as tissue and so on, then to follow that with water, because the stones remove the impurity itself and the water purifies the place, so that is best.
One has the choice between cleaning oneself with water or with stones and the like. If he wants to limit it to just one of the two, then water is better, because it purifies the place and it removes the impurity itself and its traces, so it is more effective in cleaning. If he limits himself to stones, then three stones are sufficient if the place becomes clean after that; if that is not sufficient then he may add a fourth or a fifth, until he has cleaned the place, but it is better to stick to an odd number.
It is not permissible to clean oneself with the right hand, but if the left-hand is cut off, or it is broken or diseased and the like, then he may clean himself with his right hand on the basis of necessity, and there is nothing wrong with that.
3. If the sick person cannot do wudoo' with water because he is unable to, or because he is afraid that it will make his sickness worse or delay his recovery, then he should do tayammum. Tayammum means striking his hands on pure dust once, then wiping his face with the inside of his fingers and palms.
It is permissible to do tayammum using anything pure on which there is dust, even if it is not the ground, such as if the dust can fly off a wall or the like, it is permissible to use it for tayammum. If he remains in a state of purity from the first tayammum, he may pray with it, as is the case with wudoo', even if that is several prayers, and he does not have to renew his tayammum, because it is an alternative to water, and the alternative comes under the same ruling as the thing it replaces.
Tayammum is invalidated by everything which invalidates wudoo', and it becomes invalidated as soon as one becomes able to use water or water becomes available, if it was not available.
4. If the sickness is minor, and there is no fear that using water will cause harm or cause severe sickness or delay recovery or increase the pain or cause anything harmful, such as headaches, toothache and the like, or the patient can use warm water and will not be harmed by it -- in these cases it is not permissible to do tayammum, because it is permitted in order to ward off harm, but there is no harm in these cases, and because he can find water, so he is obliged to use it.
5. If it is too difficult for the sick person to do wudoo' or tayammum himself, someone else should do wudoo' or tayammum for him, and that is acceptable.
6. If a person has wounds or ulcers or broken limbs or any sickness in which using water would harm him, and he becomes junub, it is permissible for him to do tayammum. If he is able to wash the sound parts of his body, he must do that and do tayammum for the rest.
7. If a person has a wound in one of the parts of the body that are washed during wudoo', if washing it with water is too difficult for him or will harm him, he may wipe it with water instead of washing the injured part, according to the normal sequence of wudoo'. If it is too difficult for him to wipe it or if doing so will harm him, he may do tayammum for it, and that is acceptable.
8. For the one who is wearing a dressing -- which means that there is a bad break in one of his limbs and it is wrapped up or the like -- he may wipe over it with water and that is sufficient, even if he was not in a state of purity when he put it on.
9. When the sick person wants to pray, he must strive to make sure that his body, clothes and the place where he wants to pray are free of impurities, but if he cannot do that, he should pray as he is, and there is no blame on him.
10. If the sick person is affected by urinary incontinence and has not recovered with treatment, then he must clean himself (istinja’) and do wudoo' for every prayer after the time for it begins, and he must wash off whatever has got onto his body or clothes, or put on clean clothes for prayer if it is not too difficult for him to do so, otherwise he is pardoned, but he should take precautions to prevent the spread of urine on his clothes or body or the place of his prayer, by putting a cloth over the head of the penis.
Secondly: prayer of the sick person
1. The sick person must pray standing as much as he can.
2. If he cannot stand, then he may pray sitting, but it is better for him to sit crossed legged at the times when one normally stands during prayer.
3. If he is unable to pray sitting, he may pray lying on his side facing towards the qiblah. It is mustahabb for him to lie on his right side.
4. If he is unable to pray on his side, he may pray lying on his back with his feet towards the qiblah.
5. If a person is able to stand but he is unable to bow or prostrate, then standing is not waived in his case; rather he should pray standing, and lean forward for rukoo’, then sit and lean forward for sujood.
6. If there is some sickness in his eye, and a trustworthy doctor has told him, “if you pray lying on your back then it will heal, otherwise it will not,” then he may pray lying on his back.
7. If he is unable to bow and prostrate, he may lean forward for them, and he should lean lower for prostration than for bowing.
8. If he is unable to prostrate only, then he should bow and lean forward for prostration.
9. If he cannot bend his back, he should bend his neck, and if his back is bent so that it is as if he is bowing, then when he wants to bow he should lean forward a little, and make his face as near to the ground as he can when prostrating.
10. If he cannot tilt his head forward, he should say takbeer and recite Qur’aan, and intend in his heart the standing, bowing, rising, prostration, rising, sitting between the two prostrations and sitting to recite the tashahhud, and he should recite all the prescribed adhkaar. As for what some sick people do of gesturing with the finger, there is no basis for it.
11. If the sick person becomes able, during his prayer, to do something that he was unable to do, such as standing, sitting, bowing, prostrating or leaning forward, he should start to do that and continue from what he has already done of his prayer.
12. If the sick person or anyone else sleeps and misses a prayer, or he forgets it, he must pray it when he wakes up from his sleep or when he remembers it, and it is not permissible for him to leave it until the time for the same prayer begins (the next day) and then pray it.
13. It is not permissible to stop praying under any circumstances, rather the accountable person must be keen to pray in all circumstances, whether he is healthy or sick, because it is the pillar of the faith and the most important obligation after the twin testimony of faith. So it is not permissible for the Muslim to fail to offer an obligatory prayer until the time for it has ended, even if he is sick, so long as he is of sound mind. Rather he must offer it at the proper time according to what he is able to do on the basis of the details mentioned above. As for what some sick people do of delaying prayers until they recover from their sickness, this is something that is not permitted and there is no basis for it in sharee’ah.
14. If it is too hard for the sick person to offer every prayer on time, then he may join Zuhr and ‘Asr, and Maghrib and ‘Isha’, at the time of the earlier or later prayer, according to what is easy for him. If he wishes he may join ‘Asr with Zuhr at the time of Zuhr, or if he wishes he may delay Zuhr and join it with ‘Asr; if he wishes he may join ‘Isha’ with Maghrib at the time of Maghrib, or he may delay Maghrib and join it with ‘Isha’.
As for Fajr, it cannot be joined with the prayer before it or after it, because its time is separate from the times of the prayers that come before and after it.
And Allaah is the source of strength. May Allaah send blessings and peace upon our Prophet Muhammad and his family and Companions.