If your friends are turning away from you because they think he's cooler, try to make better friends. Don't act tense or mean around these "former" friends, but take note that they're not very loyal.
If they're harmlessly just "forgetting" about you, create stronger relationships with them before introducing them to your bro. Invite them to hang out anywhere (movies, park, concert, fast food). Be active in your friendship.
Are they choosing him over you? Or does it look like he's pressuring them into following him?
