Should I add this guy on Facebook?

[SO MANY QUESTIONS!]

Here's the story...

I have another Yahoo! Answer account (besides this one)... But I'm not going to explain why I have two accounts. It's irrelevant hahaha

Anyways, I talked to a guy with Asperger's who is depressed because he has trouble making friends and communicating, because of his disability. I, of course, do not know this guy in any way.

I told him that he could email me if he ever needed more help; I always give people the option of emailing me for further help. This guy DID email me, but asked if I could add him on Facebook, since he rarely checks his email.

Should I add him? I feel bad saying no...because he just wants someone to talk to!

What should I do??
The thing is, my mom, who literally stalks me on Facebook, would say, "Who is this guy??" and probably get mad at me. Also, I don't mind messaging him on Facebook, if that's the way he chooses to communicate...But, couldn't I prevent him from seeing my statuses and stuff? I'm not creeped out by him or anything...It's just that...I don't know him!