Qn21: My father has abandoned the prayer, commits illegal intercourse, comes home late and doesn’t speak to us or my mother. I saw him come home once and arguing with my mother; I entered upon them and sided with my mother which angered him. Am I sinful in this?

2) If you are from in a non-Muslim country, I order you to advise the father to fear Allaah ‘Azza wa Jal, and to remind him that leaving the prayer is disbelief, and if he dies upon that, then he dies a disbeliever. If he accepts your advice, and this is what we wish for, then this would immediately solve his situation with his family and his wife. However, if he refuses, then there is no problem in you standing by your mother, you are not sinful in this. Even if it reaches the extent where you’d have to go to the authorities about it as, if the situation is as you describe, then this man is commiting Dhulm (oppression). You should advise him but not curse or shout at him. If he becomes physically violent and attempts to strike her, then it is permissible for you to intervene, even if this means going to the authorities and this is based on the hadith of the Prophet (sallallahu ‘alayhi wa sallam) who said, ‘Support your brother whether he is an oppressor or an oppressed.’ Those around him said, ‘We understand about the oppressed but how can we help the oppressor?’ and he (sallallahu ‘alayhi wa sallam) said, ‘By stopping him from oppressing.’