You're right regarding the seizures. There is nothing you can do to help. I understand that will come across as blunt, but try to remind yourself that his health isn't your responsibility. It requires a shift in mindset, but you'll be a lot happier in the long-run. It's unhealthy to worry constantly about someone else. He wouldn't want you to be worrying about him either.
With your other friend your two best options are:
- confront him
- stop being friends
If you think that his current behaviour is short-term, or the friendship is salvageable, then the first option would be better (given what you've said about him, via message would be better than face to face). Have him realise that you're no longer going to put up with being treated this way. If he thinks you're over-reacting, in the wrong, or doesn't care about your friendship then don't fight him on it; simply walk away. You know what his priorities are and you're not one of them.
If you don't think he is likely to change or that the friendship is worth continuing, I'd opt for the second option. You don't need that sort of negativity in your life and shouldn't be expected to have to put up with it just to please other people. Having mutual friends doesn't mean that the two of you need to be friends too. Be polite, hang out in a group, but don't spend time together or chat one-on-one.
