Issues

I have a tendency to say yes to things without really thinking it through and because I want to be nice.  
So anyhow, there is a family friend who I dated briefly a very long time ago.  He has mental issues and is considered disabled.  Recently he was diagnosed with stage 4 lung cancer.  I wanted to show him support so I have visited him and talked to him online.  He likes to say love you, so I said it back, as a friend. 
So the other day, he found out that I might be camping with my niece and he asked if he could sleep with me.  I thought he meant in the camper, but he literally wanted to sleep in the same bed with me, just to cuddle.  I was thinking at first that it might be nice for him because he is very sick and might like a little affection.  I said yes, but then the more I thought about it, knowing his history and ways, I told him I changed my mind because I felt uncomfortable about it.  He didn't take that well, saying, "but it's me".  I told him that I have learned that I need to say no and stand up for myself if things don't feel right, so it's no.  
He copped an attitude.  So then yesterday, every time I posted something online, he would leave some snarky comment about how I made him feel uncomfortable and how I said "I loved him" etc... 
I responded in a brief way and kept it simple.  He kept it up and was commenting on everything I posted.  My online friends were starting to notice, so I deleted his comments.  They kept continuing so I just blocked him.  
I feel a little guilty, I guess in a way because maybe I should be feeling sorry for him because he has cancer and is going through treatment, but then I thought, that is no excuse for bad behavior.  When I had cancer and was going through treatment I didn't act like that.  So, if he wants to label me as a bitch, so be it.  I don't owe him anything.