What is the ruling regarding a sick person who suffers from frequent urination urinating into a diaper, and is it permissible for him to combine prayers upon returning home due to his clothes becoming impure and his inability to change them?

It is obligatory for a Muslim to perform prayer at its appointed time with purity as much as possible. Whatever obligations he is unable to fulfill are waived for him, as Allah the Almighty says: (Allah does not burden a soul beyond its capacity).

If he is unable to remove impurity from his body or clothing, or if it is difficult for him to do so, he should pray at the time even with the impurity present, and not delay the prayer.

It is permissible to combine two prayers (Dhuhr and Asr) and (Maghrib and Isha) when there is difficulty in performing each prayer at its appointed time, such as in the case of illness. The combining can be either a premature combining (jama' taqdim) or a delayed combining (jama' ta'kheer), whichever is easier.

If the patient suffers from urinary incontinence, he must perform ablution for each prayer after its time has begun, and wash whatever affects his body, and use a clean garment for prayer if it is not difficult for him. Otherwise, it is excused for him. If he is unable to change his clothes or diaper, he should pray at the time according to his condition, and the presence of impurity does not harm, because observing the prayer time is more important. In this case, he should not combine the prayers as long as he does not benefit from combining anything due to the inability to achieve complete purity.