The World Federation One Stop Fiqh

Ruling 2719

If a person notices the signs of his approaching death and has lapsed (qaḍāʾ) prayers (ṣalāh) and fasts (ṣawm), he must make arrangements such that he is confident that they will be made up on his behalf after his death. For example, he must make a will that someone is to be hired from his estate to perform them. In fact, if he does not have an estate but deems it probable that someone may perform them free of charge, again it is obligatory (wājib) on him to make a will [regarding this]. However, if there is someone, such as his eldest son, whom he knows would perform his lapsed prayers and fasts were that person to be informed of them, then it is sufficient for that person to be informed and it is not necessary to make a will [regarding this].