My other brother suppose to be moving up to move in with us this weekend since he can't afford his…

My other brother suppose to be moving up to move in with us this weekend since he can't afford his rent now without his dad. I don't know how this is gonna work out lol. Honestly though. His 5 year old is mean. Like sneaky mean. I also think he has autism and adhd. And he won't be mean to my son.... I won't have it.. His mom nor my brother discipline him so yeah idk how this is gonna work out with them living with us for awhile