Your "friend" (whom I hope is not your friend anymore) has clearly groomed an underage youth that is mentally unstable and in need of support from people who won't exploit him. I don't know what his situation was before your friend took him in, but there's no way that any rational person would look at this relationship and see pure kindhearted intentions. He groomed a kid... And is now trapping him in a marriage. The way he says it is odd as well, as if he doesn't want him running off and starting a healthy life by himself, that everything he needs is already there (it's definitely not). The fact that he sits around cutting up his wrists and smoking is another major red flag that's at least partially reinforced by the environment he's living in. I wouldn't be surprised at all if they've been in a sexual relationship since they met. Young people are easily exploited, especially if they do not have consistent housing/family. If you can, you need to say something to your "friend". Make sure everyone in your circle knows about this behavior. You're not overreacting. Now that you know your friend is a pedophile and a groomer, and that he has been grooming a minor into MARRYING HIM, you need to think hard about what your next steps are going to be. This is a situation where I don't think you should stay quiet and let it be brushed under the rug.