Okay, firstly you need to understand that no one can just snap out of depression. You can help someone cope with those feelings and help them at the very least make it out of the episode, but depression is something that’ll be a part of someone for their entire life. It’s just that they may have very effective coping mechanisms that it doesn’t surface to other people. I know your intentions are pure, so I’m trying to respectfully make you aware of this fact.
Second, great on you for wanting to help. But make sure you aren’t doing this for the sake of advancing a relationship with him. He is still a human with his own preferences, and is not obligated to go out with you just because you helped him. You need to be mentally prepared for the scenario that he doesn’t want a relationship with you. But if he does, that’s great, and you can move forward accordingly.
Lastly, make sure he knows your intention. He may become unreceptive to you and your help if he feels you are trying to do a favor for him with the expectation of him doing something in return, whether that be a relationship or anything else. Make sure he knows you are helping him for the sake of helping him. And who knows? Maybe he’ll be attracted to that selflessness you show.
I wish you the best of luck and hope that whatever is best in this situation manifests for you.