So i am having very serious drama w/friends any advice?

SO THERES MY FRIEND NIKKI...SHE LIKES A BOY THAT SHE DATED AT ONE TIME BUT NOW SHE RELIZES WHAT SHE PUSHED TO THE SIDE BECAUSE OF NICKS SISTER. NOW HE IS DATING OUR FRIEND SHELBY... WELL AS HE IS DATING SHELBY HE IS ALWAYS SHARING HIS EMOTIONS WITH NIKKI..SHE CLAIMS THAT SHE IS IN ♥ W/THIS GUY NICK.. BUT ANY WHO SHE DONT KNOW WHAT TO DO THEY ARE CLOSE TO EACH OTHER AND HE TELLS HER THAT HE WIL ALWAYS HEVE HER NO MATTER WHAT... BUT SHE THIS THAT HE WANTS TO MARRY HER...WELL HE IS A RELATIONSHIP RIGHT NOWW AND HER LIFE IS ALL TWISTED UP AND AROUND I HAVE TOLD HER TO MOVE ON UNTILL HE MAKES UP HIS MIND... AND THAT THERE ARE ALOT MORE FISH IN THIS D*** SEA...BUT SHE DONT WANT TO HEAR THAT CRAP SHE WANTS TO HEAR WHAT HE'S GOT TO SAY BUTHE WONT SPEAK NOTHING BUT THE WORDS I♥ YOU AND I WNAT YOU REALLY BAD. T HE'S IN A RELATIONSHIP....WHAT SHOULD SHE DO AND WHAT SHOULD I TELL HER???