When Aging Parents No Longer Walk with God

I would love for you to do a video on how we, as Christian adults, can deal with our aging parents when they let us down and commit egregious sins. My husband and I have a parent who just left another wife for no reason other than he was tired of being married to her. We’re having a hard time, primarily because we have lost all respect for his dad. We have always thought he was a believer, but he quit going to church and shows no remorse for abandoning his wife.