Dealing with a dysfunctional family?

I am married with an 11 week old son. My extended family have always made life difficult and stressful. Last year, things got really bad, and we decided to have a few months aways from them, to heal from the hurt and give them time to sort out their own issues. My father is an abusive, destructive alcoholic, and my brother is a selfish, manipulative liar, and my Mum stands up for the both of them. They never take responsibility for their own behaviour - they blame everything on other people, which makes me think they will never change. My question is, should I introduce my son to them or not? Is he safer away from them, or should he know his grandparents? Should I just include my Mum in my life, or will that make my Dad and brother even more angry and vindictive? We are tired of living with fear and just wish everyone would try and get along, and grow some love in their hearts rather than hatred and conflict all the time.