Why do you care about his friends? This is your life, love it or leave it.
I'm dating a guy but his friend does not like me?
Well forget his friend ok. Or if it bothers you tell your boyfriend his friend is rude to you. If he cares enough he will talk to his friend.
Don't worry about his friend if you like each other date, forget what his friend wants! He might like you too - that's why he's jealous.