I agree that maiking him a ward of the state is your best option now, you've exhausted all others to no avail.
I know it's anything but easy, but it's time for junior to sink or swim, instead of drowning the rest of the family....
I love you Blue, and you know I admire you to no end, the things you've done for your family, the lengths you've gone to for your son's protection, but it's time to shift priorities, he doesn't want the help, and the rest of you want AND need safety.
You are all in my thoughts and prayers