S.G.
It sounds like you have gotten a lot of advice, so I will affirm what the others have posted and what my doctor said. My son is now 10 and still has nose bleeds (so bad it has come out of his eyes before). We have a whole house humidifier we crank up and we also put a smaller one in his room. We put Vaseline on a Q-tip and swirl it around in his nose before he goes to bed. This really does help. After 5 years, I think we have finally found the right combination to help with his nose bleeds. The good thing is, now he is old enough to take care of it himself and we don't freak out every time it happens. If these things don't work for you, I would take him to see his doctor. When my son was smaller, his doctor put him on a seasonal nose spray.