Chloe-
I think you have ever right to be angry at this guy. It sounds like he is never held accountable for his actions.
I am not sure that you can really help him. But, do keep your good boundries concerning him and take good care of yourself around him. In the "Freinds and Family of Alcoholics" forum here there is some excellent info at the top of the page on what you can do read all of that and you may find the answer you are looking for.....
....and welcome to Sober Recovery.