Mom left dad and moved in with her parents.
I am curious as to why your mother left your dad and if this was ever revealed to you? Was it primarily due to the on set of her mental illness and that placed just too much stress on your family? You mentioned that later on in life you bonded with your father with the help of his wife. I am wondering why you may have been fearful of your father? (excluding the example you gave of his dislocating your shoulder by swinging you around.). Was it mainly the fact that you spent most of your time with your mother and infrequently saw your father?
Somewhere in the past, maybe an interview or an article, I was aware of your being sometimes homeless as a child. However, your story above is more complete and takes great courage to tell. As you relate, your hardships and trials were many. However, most importantly as you point out, there were crucial supportive people at the right times and places in your life that allowed you to overcome a very difficult childhood! The follow through on this is it may be possible that each one of us could play a supportive role in someone's life that ultimately make all the difference in the world as to the outcome of their life.