Chic, I say this gently, you know I care about you. You are not qualified to dx him. You are too close, you are manipulated and you are "The Mama".
You might start looking for help and inside information at your own physician's office. Your primary care doc has resources, his nursing staff, they refer people. You just have to tell them what you told us.
I don't know your son, but from my point of vision, you need to cut the umbilical cord. He can't grow without falling...it seems you are wearing yourself to a frazzle running around carrying a mattress to cushion his falls. His issues are stealing your happiness, you can't have your grandchildren for a sleepover without jumping through hoops. That is ridicules.
See if there is a behavioral health division in your county? I will try to check on how it works from my state once I get to work....I don't deal with that too much, but I know where to look.