Is the obligatory prayer waived for a Muslim who is unable to move and is not paralyzed, but suffers from involuntary urination and there is a possibility that there is impurity on his clothes without his knowledge?

Prayer is not waived for a legally responsible individual as long as they retain their sanity. It must be performed to the best of one's ability. If one is unable to stand, they pray sitting; then, if unable to sit, they pray lying down, even if only by gesturing with their eyes. A person afflicted with urinary incontinence performs ablution for each prayer after its time has begun and takes precautions with a cloth; what exits afterward does not harm their prayer. As for the presence of a suspected impurity on clothes without knowledge or certainty, it does not invalidate the prayer, nor is there any sin in it, as the default state is purity.