Sometimes giving someone time to just let the news settle is all they need. This doesn't necessarily mean that he's running away from you, doesn't want to be with you, or doesn't want to help you, it could be as simple as wanting a moment alone to let the news sink in.

Even in the best situations things can go wrong. Sometimes wanting to be with someone and stand by someone's side isn't enough to be able to do so. He has just as much of a life and emotions as you, and it is very possible that he doesn't feel ready or able to handle this with you. That wouldn't even make him a bad person, it can happen to the best of people.

When he is ready and able to talk to you then he will. Until then, if he wishes to be alone there is sadly little that you can do. If this, however, were to continue for an extended period of time (weeks) I would probably consider him out of the picture. But a few hours or even a day or two isn't much in the big scheme of things, even if it is worrying for you. When he gets back in touch with you, perhaps explaining that you are ok with him having his alone time, but you care for him and worry about him, and just knowing that he's ok and safe is really all you need. Explaining that it isn't a matter of knowing where he is every moment, but simply understand that he hasn't left you alone is what's important to you. I have gone through this issue myself. Sometimes when I need some time alone I tend to forget about those that are important, and there were a few times that I left myself MIA to my boyfriend, unknowingly leaving him worried and stressed. A simple conversation was all I really needed to get my mind back on the right track.

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So when you're happy (Hurray!), or sad (Aw!),
Or frightened (Eeek!), or mad (Rats!)
An interjection starts a sentence right.