My mother is an old woman whose right leg was amputated up to the knees and her left foot was amputated as well. She also suffers from (excessive) obesity so she cannot move easily and, therefore, cannot direct herself towards the Qiblah during the prayers except with great difficulty. Is it permissible for her to perform the prayer without directing herself towards the Qiblah due to her health condition that was explained above?

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.

Directing a worshipper's face towards the Qiblah is a due condition for the validity of the prayer and a worshipper is not exempted from observing such a condition except in the case of inability. Therefore, if your mother is physically unable to direct herself towards the Qiblah and there is no one around to help her face it when performing the prayer, she is exempted from this obligation. However, we would like to highlight that the fact that your mother had her leg or hands amputated or suffers from excessive obesity cannot be considered a valid excuse to render her physically incapable of simple movements in order to direct herself towards the Qiblah. Moreover, we would like to remind you that one of your brothers or sisters should be with your mother during the times of prayers to help her direct herself towards the Qiblah. She is allowed to perform the prayer in another direction other than that of the Qiblah only if she cannot physically move and there was no one to help her direct herself towards it or there will not be enough time except to perform the prayer without directing herself towards it before its end time.