The challenge with these kind of issues is that they are not ones people like to share. A social network requires profiles to be public & discoverable or people can't network.

I do think a site that people can privately create a profile, and reach out to curated experts, doctors, etc would be a great resource, but that being said - their are a few sites doing this in the health space (ex: http://healthtap.com).

Build a social support network will be tough, and the hard things to solve will be the social part (ex: do you require profiles to use real identities? are these profile indexed by google?, etc).

Hope that helps a bit.