How should siblings and I handle sharing care of Dad and not violate our individual lease agreements?

I live at dad's house w/ my youngest son (13) & have had to resort to "sharing custody" of dad w/ my bro, & sis due to the amount of care he requires increasing. It is overwhelming for one of us to do this all the time. He gets into mischief or trouble if left alone too long at the house. So, he goes to my bros (down the street), and my sis' in apt. He stays 3or4 days w/ea. Issues of violations in lease agreements have arisen. I say, "tell the truth". They want to hide him. (He can't be on theirs or rent increases). He is technically not living there as his mail comes here. But, he is a handful & he cannot be left alone too long. But, is it against a person's lease (in general) to stay w/ family member for a few days here & there? What else can we do? He doesn't want to go to assisted living. He wants to be w/ his kids. (He also calls a lot of attention to himself by rummaging through trash & talking to people he doesn't know). He doesnt want to go to the senior center any more. Just sticks to us like glue. How do we keep him happy & NOT get into trouble?