Qadha Salat Of The Father
Rule 158
If the father did not offer some of his obligatory prayers, and did not care to perform the Qadha in spite of being able to do so, then after his death, according to Ihtiyat wajib, it is mandatory upon his eldest son to perform the Qadha - provided that the father did not leave them as a deliberate act of transgression. If the son cannot do so, then he may hire someone else to perform them. The Qadha prayers of his mother are not obligatory upon him, though it is better if he performs them.
Rule 159
If the eldest son doubts whether his father had any Qadha Salat, then he is under no obligation (to perform any Salat).
Rule 160
If the eldest son knows that his father had a certain number of Qadha prayers on him, but he is in doubt whether his father offered them or not, then, according to Ihtiyat wajib, he must offer them.
Rule 161
If it is not known who is the eldest son of a person is, then it is not obligatory on any of the sons to offer their father’s Qadha prayers. However, according Ihtiyat Mustahab, they should divide his Qadha Salat between them, or should decide between themselves for offering them.
Rule 162
If a dying person makes a will that someone should be hired to offer his Qadha prayers, and that hired person performs them correctly, then the eldest son will be free from his obligation.
Rule 163
If the eldest son wishes to offer the Qadha prayers of his mother, then in the matter where the loud or audible whisper recitations in Salat is concerned, he will follow the rules that apply to him. Therefore, he should offer the Qadha prayers of his mother for Fajr, Maghrib and ‘Isha, loudly (reciting the Surahs out loud).
Rule 164
If a person has to offer his own Qadha prayers and he also wishes to offer the Qadha prayers of his parents, then whichever one he offers first will be in order.
Rule 165
If the eldest son was a minor or insane at the time of his father’s death, then it is not obligatory for him to offer Qadha Salat of his father when he attains puberty or becomes sane.
Rule 166
If the eldest son of a person dies before offering the Qadha Salat of his father, then it will not become obligatory on the second son (to offer them).