My DS's dad has bipolar. Managed with meds, no episodes for at least 5 years.
However since then it is obvious he is a shadow of his former self. Probably depressed. My son no longer wants to go to his house. It is dirty and the smell is evident when he opens the door at pick up time. Dad does cares but just sits and hardly speaks to son.
Me and DS dad get on, there is no animosity.