Assalaamualaikum
My parents have been having marital problems for many years (poor communication, arguments, etc) No effort was made by them to sort it out. My father (70yrs) then recently got secretly remarried to a woman half his age. He told my mother after a few months of doing so. She is devastated. We all are devastated. He is in the the tabligh jamaat. He says what he did is sunnah.
I am disgusted by what he did and I know it will be sinful to break ties with him. But I can’t stand being in his company. What is the minimum I have to do in terms of maintaining ties with him, so as not to anger Allah ta’aala.
Jazakallah for your time and advice