What is the ruling on the prayer of an illiterate elderly man who suffers from diseases that prevent him from moving, is unable to perform ablution (wudu'), performs tayammum with a stone, sometimes prays sitting, and has urinated on his clothes?

If the father is of unsound mind, he is not obligated to pray due to the hadith: "The pen has been lifted from three."

However, if he is of sound mind, prayer is obligatory for him and is not waived. He must make up for any missed prayers. He is required to fulfill the conditions and obligations of prayer that he is able to perform.

If he is able to use water for ablution (wudu), he must do so, and tayammum (dry ablution) is not valid, unless using water would cause him unbearable difficulty, in which case he may perform tayammum.

He must perform istinja (washing after relieving oneself) and avoid impurities if he is able. Tissues are not sufficient if urine has spread; rather, washing with water is required. If he is unable to perform istinja or finds it difficult, it is waived for him. He is then required to change clothes that have become impure for prayer, and if he is unable, he should pray in them.