Is there an obligation to repay the outstanding devotional actions and debts of the deceased?
It is not obligatory (wājib/ fardh) for close family members to perform the outstanding devotional actions of the deceased, such as lapsed (qaḍāʾ) prayers, fasts etc. This is because such an obligation is not established in the Quran or sunna of the Prophet. However, it is recommended, nonetheless, to perform good deeds on behalf of the deceased, which may include offering any of their lapsed prayers or fasts. This is particularly encouraged in reference to Hajj based on a narration in which prophet is believed to have encouraged Khathʿamiyya, a female companion of the Prophet, to perform pilgrimage on behalf of her father (Wasāʾil al-Shīʿa 27:52).
It should be noted that the issues concerning the right of people (ḥuqūq al-nās) are not exempted and must be fully paid. Quran (4:116; 4:12) is explicitly clear that the closest to the deceased must pay back any debts incurred by the deceased to their debtor.