Al-salaamu `alaikum wa rahmatullahi wa barakaatuhu! I a person in illness can't afford neither to stand, crawl, nor sit, and he/she would like to perform a prayer. In the first place, how could he/she perform an ablution? Who could help him/her? What if there's no place for tayammum? What if he could not able to move his/her arms and hands? Thank you very much and jazaakumullahu khair...

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

A sick person must perform ritual purity according to his ability, as Allaah Says (what means): {Allaah does not burden a soul beyond its scope.}[Quran 2:286]

If he is able to perform ablution, he is obliged to do so, but if he is not able to perform ablution by himself and he finds someone to help him, then he should seek his help. If he can’t find someone to help him, he is obliged to perform Tayammum (dry ablution). If he is not able to perform Tayammum by himself and he finds someone to perform Tayammum for him, then he should seek his help. If he can’t find a place where to perform Tayammum, then one may bring him some soil in a dish or the like so that he may perform Tayammum. If he is absolutely unable to do all this, then he should perform the prayer as he is, even without ablution or Tayammum for the previous verse and he is not obliged to make up this prayer according to the preponderant opinion of the scholars .

Allaah Knows best.