Definitely take care of yourself. It can be easy to get rundown supporting someone with an MI. My partner and I both have an MI and go through depression. It's easy to get overwhelmed with concern, you both wind up depressed...no good. You sound like a great friend.

Random idea came to me: Is your friend female? If so, give her a stuffed animal! They are snuggly, cute and a reminder that she is loved.