I don't know what to do with my son anymore?

I think you need to stop making this about you. Your son is in great pain and probably don't know how to talk to you based on how your reaction. The fact that he comes up to you meant that he is reaching out for help. Don't force him and counseling is a great way to help him deal with what he is going through. Unless your son gives the counselor permission to tell you what he discussed with he or she they are not allowed to say anything to you. Maybe you need family counseling to talk as a family of how this incident have impacted your lives. Your son probably drinks because he is trying to numb the pain he feels. I understand how you may be feeling because your nephew has done it, but give your son some time and maybe it will be good to go to family counseling so that you can work on the problem together as a family.