What if sometimes I don't know what to say?

Maybe I should just write I don't know what to say, but I support you and hope you feel better soon? Would that be a good idea?

Maybe I should post, I read your post and I'm thinking of you, even if I don't have anything to say.

I think that helps me. People don't have to write much. They can just write they are thinking about me and that makes me feel cared about.