He needs to get together with a therapist, straight/gay alliance, gay support group, counseling center... SOMEONE. You might see if there's a local PFLAG chapter near you. Being a 17-year-old, he probably won't take kindly to you trying to "force him to talk to someone." He needs to believe that when he decides to talk to someone, it is of his own free will. Try your best to take your cues from him, being supportive when you need to be and backing off when he needs his space. If he's never seen any "It Gets Better" videos or read the book by the same name penned by Dan Savage, that may help him to feel not so isolated. We all deal with our coming out and sexuality in different ways; I'm sorry that your son is having such a terrible time of it and wish I could give him some "magic spell" to make it all go away. Both of you hang in there; this is a rough road to travel but no matter what happens, keep communicating (while arguing isn't the best way to do that, is still is communication) and try to see past the pain to the PERSON. And remember: the two of you ARE NOT ALONE. There are many people who have gone through this and there will be many more. The world needs you BOTH; trust in that. Peace and Love to you both.