What would you do in this situation?

I met a guy at uni through a uni sporting club. he is nearl 10 yrs older and is a nice enough guy. throughout uni i got to know him better and have since been good friends with him. we rarely catch up in person but used to chat over phone and online regularly when i completed my studies. he was always talking to me every day for weeks then would stop communication for weeks. i email or sms him and he wont reply. he has depression and has told me he really loves me. he is a virgin and has never had a girlfriend. i feel flattered he has strong feelings for me and he is so sweet but i, put simply, don't feel the same way about him and have told him this. it has been 6 months since we kept in touch regularly. recently he sent an email and said he feels weird talking to me because he feels for me so strongly. i feel so nice he feels this way but still cant consider going with him. i dont want to be mean but dont want to put up with his depression. hes a really bad case and i'm to be cont..