Hows to prepare for an 11 yo with behavior issues?

I have a family member I may be getting custody of after the school year ends. He has had multiple suspensions and was step away from being expelled before switching schools when he moved to a therapeutic foster home. He is not physically violent and has a lot of anger issues. Swears and back-talks (more than a typical 11 yo, lol). We are committed to him and dealing with his issues but would love any tips or resources (books, websites) in dealing with an angry child.