I can’t really offer any advice about wild rabbits, because I’ve never had any experience with them. It’s commendable that you saved him and are trying to rehabilitate him.
However, you should definitely quarantine this wild bunny from your current bunny(s). He could have all manner of mites, fleas, parasites, etc. that you don’t want to transfer to your house pets. Keep him in a separate room if possible, wash your hands after touching him, and if possible, change your clothes (and wash those asap) after.
I would handle him as little as possible – you don’t want him to begin to associate humans as “safe” if you’re planning to release him back to the wild.
Do you have a local wildlife center or wildlife rescue? You could call them and ask for tips on how to help him – and they might be willing to take him in and rehab him themselves.
ETA: Lol, I just saw that Jersey mentioned the same thing about the wild life rescue. Maybe this list will get you started… There are a couple listings for rescues in Huntington Beach. http://www.southeasternoutdoors.com/wildlife/rehabilitators/california-rehabilitators.html