Is he telling the truth

This is mostly directed at people who know about high blood pressure and the effects it has. But any feel free to read or comment.

My ex boyfriend is telling people that he is going to go blind in 10 months and that he probably will not live past 20 (he is 17 right now). He says this is because he has high blood pressure. He has only known for like 3 months and is on medication for it but apparently it isn’t helping and it’s not going down no matter how well he eats or exercises. However he does have a tendency to lie/exaggerated how bad things are to make people feel bad for him. We are currently in a musical together, but other than rehearsals and the group chat for it we haven’t really been in contact. I actually asked him to not talk to me unless necessary. (He was emotionally abusive) I was the one who got him to audition when we were still dating and everyone in the cast in knew me first. I didn’t want to tell them the truth about him until after the show because I didn’t want there to be drama. But now everyone is concerned about him and he got the director to help him put on a musical because she think he is going to die he. (This hasn’t started yet but they have been talking about it) because of my past experiences with him I don’t believe that this is true, he probably does have high blood pressure but everything I looked up about it didn’t seem to suggest that this is something that could happen. I just want to be armed with facts so that if I ever do tell everyone that he is lying, I can make my argument well. I’m also a bit afraid though that this is true and I don’t want to accuse him that it is not and then he dies. I also just don’t want to look like the petty ex who is spreading lies about their ex.