parenting time

I'm filing for sole custody and can't figure out if this man even deserves patenting time, with his other daughter he does what he has to. Now I do not trust his gf and it sounds childish but she's one of those young girls, she smokes she has two kids who she doesn't even take care of, her place is infested with bugs and him on the other hand still lives with his mother. I love his parents, but I don't want his mother doing all the work while he's working or he's out partying or spending time with his gf. I know this will happen because I was in a relationship with him and he cheated left me home with his older daughter on his parenting time and went off. Advice? Some peace of mind anyone