(((((((((((mygrelmin)))))))))
Sorry to hear about your son. I have a son the same age and totally understand not being able to "make" them go to appts. I don't have an answer; I wish I did. All I can say is keep telling him you love him and that you are there for him. Unconditional love and support without nagging is the best route, in my opinion.

17 is a gray area age unfortunately. They are considered an adult in some areas, a minor in others. But, if he becomes suicidal, a call to 911 will get him help whether or not he wants to go. There are ways to get him there and while it's painful, at least he will be alive.

Wish I could say more to help. I wish the same for my son. Good luck to you and your family.