My sister vs. him - his friends vs. me Please I need help I have only met these friends once each?

Sister is jealous of my boyfriend. She was happy when we first got together because she had a man. When they were breaking up she wanted more time with me and I tried to be there for her but at the time I was falling in love. Now that she has no one in her life all she can do is say negative things that she makes up as the mood fits her about him to family members (in hope of what I don't know). They believe her!
His friends (he has known forever- I've know him 6 months)
are lying to him basically saying I have a bad attitude with them when he is not around. 2 friends I've never seen 2 gether I never see his friends without him and he is gone out of the room less than 2 minutes so how bad of a mood swing could I have with people I dont know? Problem he believes them. They live in another state and want him to move back there. The only reason he is here is because of me?
Do I tell these people to back off: do I tell him friend r lying or ignore it HELP! This is stressful for him

you should talk to your sister and tell her that yes you understand she's mad but don't take it out on your relationship with your boyfriend. and try to spend more time with her she's in a bad place and maybe she'll stop if she feels that you are still there for her. as for your boyfriend's friends explain to your boyfriend that you understand that he's known them forever but they are just trying to break you two up. tell him that you want to be friends with them( only if you do) but their aren't making it easy. and tell him that there is now way you could get a bad attitude in the time he's not in the room with you and his friends. tell him that your not trying to break his relationship with his friends but that he needs to talk to them and explain the deal to them because it hurts you when he takes their side and you haven't even done anything.
good luck

YOU DON'T HAVE TO WORRY OF ANYTHING,YOUR SISTER IS YOUR SISTER,YOUR BOYFRIEND IS YOUR BOY FRIEND.YOU GIVE TIME TO YOUR SISTER AND GIVE TIME TO YOUR BOY FRIEND. HAVE YOUR QUALITY TIME WITH YOUR SISTER BUT INTIMATE TIME WITH YOUR BOYFRIEND.SISTER WILL ALWAYS BE YUOR SISTER,YOUR BOYFRIEND WILL ONLY BE YOUR BOY FRIEND UNTILL YOU JOIN TOGETHER WITH MATRIMONY....THEN THINGS WILL BE DIFFERENT

ur friends and family rnt the ones that have to be happy with ur 2's relationship its u 2 that have to be happy its ur lifes noone can make that desition but u 2 but if ur happy **** everyone and anything else yadd'da

well i do anything to make my sister stay out of my personal life