I’m not a parent, but it seems this is deeper rooted in your relationships with people and how you’ve coped with being hurt in the past. The difference here is if you want to continue being in his life (it seems like you do), you owe it to him to get help or counseling so you don’t pass it on to him. Speaking as the adult child of 2 alcoholics, parents need to always keep in mind your children didn’t choose you, either. But you work with what you’ve got if you want the relationship.