How cans i ask him if i can come see him?

I have a guy that I was friends with last summer and I fount out yesterday that he has cancer from his bestfriend..she made a tweet n that's when I found out..But idk if were on "good terms" meaning cool/friends. Last time I talked to him he invited me to a get together he was throwing and I didn't show up , after that I went on facebook/twitter/instagram and he UNFRIEND/UNFOLLOWED me on everything.So im kinda scared to ask..I asked his bestfriend and she was like just message him in see what he says but im scared(a little).HOW COULD I ASK IF I CAN SEE HIM?