Gem,
Sorry you're going through this. It would have happened sooner or later....running into him with someone else or hearing about him with someone else....BUT; shame on your bro for telling you "he's doing better than ever". Good grief, that's really not needful to tell you that and the last thing you need to hear! I know he's apologized, but you can't take back words once they're spoken. In my mind 'no contact' means no contact, na da, nothing; not through friends, family or anyone else. But a lot of people don't get it.
It's true it takes at LEAST 3 months if not MORE to get over some relationships. And it's also true that breaking up with someone you were addicted to is like withdrawal being without you 'substance'. Chemistry and hormones are involved, so thank mother nature for that one.
BUT, you can train your mind and your thoughts patterns to "not go there"; not engage in any way. It may seem that hormones rule the world, but we also have a powerful weapon: our brain. Logic. Common sense. Problem solving abilities. It sounds like you are having a hard time getting him out of your mind. Try to engage in other activities that engage your mind: exercise, music, hobbies, shopping, other activities. There's all sorts of things you can do. Really, in my opinion a person can be so liberated and happier without the weight of a relationship.