To check up on him or not?

So one of my closest friends has been a real dick lately so I've been ignoring him but yesterday he messaged me with the hi how are you and I was very short with him but give his situation (has depression and was previously suicidal - hasn't told anyone about it except me) I was wondering if I should be nice to him regardless? I have a soft spot for him even though he's been treating me like shit lately and I obviously care about him but I don't want to be his door mat ya know. He need to realize that if he wants to confide in me then he needs to treat me with respect and just be nicer. So what should I do?