A friend

A 12 year old friend of my brother has been having severe nose bleeds for no reason. As in gushing nose bleeds, sometimes several times a day. He also has a problem with vomiting blood. These are symptoms for a few different diseases, all of which are basically fatal, so we're really worried about him. He was taken into emergency surgery about 3 days ago but was back in school a few days later. The doctors won't tell him what's wrong, but in order to operate, they had to know the problem. In other words, I don't think his parents are telling him for a reason... I think it's bad... Please pray he's okay.

I'll be praying for him. How is he doing? What are the possibilities of him having? I can think of a couple but I don't know all of his symptoms.