What do I do?

I've been in this kind of weird long-distance, online type of a relationship with a guy I met over a weekend in New York. We text, snapchat, and FaceTime, but we live on other ends of the continent. He's about to graduate from military school and be deployed as an active duty soldier. I'm also going to graduate from college and will hopefully be going to graduate school, I'm just not sure where yet. I will definitely stay in the west. He recently opened up to me and told me that he's had a lot of concussions and now has depression and suicidal thoughts that he's been talking to mental health professionals about. He tells me that he really likes me and that he's so glad I can support him. I want to help him as much as I can, but as someone who struggles with depression myself (in addition to an eating disorder), I don't think it's healthy for me to get sucked into this situation. I know it sounds horrible and that what he's going through is beyond his control, but I'm not sure I want to continue to communicate with him. I don't really know if we're in a relationship, so I don't know if I need to "break up with him" necessarily. I want him to know that I care for him and I'm not scared off by depression, but I think there are just too many external factors making this the most complicated, impossible relationship (or whatever it is). I really do care about him and his wellbeing, I just don't think I'm in a place to give him the support that he needs. Should I cut this off? Or would it be better to stay in what ever kind of relationship this is?