I think the first thing you should try to do is get yourself in a calmer state of mind. Different techniques work for different people. So, sorry, I can't really recommend anything deeper than that.

If you manage to soothe yourself, from the sound of it, I think all you can do is just show him how much he means to you. Try to reassure him that people that vile don't even deserve someone as humble as him. In the end, all you can really do is just be there for him in a positive manner.

Sorry. I know this didn't help at all. -_-