Friend's Little Bro Trouble......

This is something I have come a cross my friend's little Brother was a good kid once nice, kind and well just a decant person...... Now all of a sudden he doesn't like me, he doesn't want me to go over to his house (My Friends house) and I'm not the only 1 he hates for no reason my friend however has taken to following his little brother's rules which has made it hard for us to talk, chat online and even well take it in turns to play in the bedroom at his house another thing i noticed on my last bedroom visit was that his little brother was now listening at he door while we were ......well u know......

This in turned caused a small fight between us in which i told him that his little brother is walking all over him and that its time to put him back in his place.....

my friend's reply was along the lines of i don't want to lose my brother i have lost my sister i don't want to lose him to.

my reply was your brother will keep doing this to every chick you meet if you don't start to foot down now......

I just don't know how to make it clear to him that its his brother that is ruling the roost and not him the owner of the house....

should i just give up on him or keep hoping that soon he'll get the message to put his foot down!!!!!!!!!!!!!