I need some advice on this:

I have PTSD and have problems forging relationships. I have one close friend who has his own slue of problems (neurosis and family issues, none of which we can relate on) and is only 15 (my age). He wants to help with my problems, but I make a point of only asking for help from those with a reasonable amount on their plates, so they don't have to worry about me as well as their own problems. I have told him all of this and he seemed to be really hurt. How can I rephrase it so it sounds less abrasive? Or should I just let him in?