How do i tell someone i don't like them as more than a friend?

My boyfriends best friend, (who i have never met before and only talked too a few times on facebook and is sick as well). i got a text saying he liked me and i thought it was just lads messing around on his phone so i was like whatever but then one of the other lads put it on facebook and hes expressing his like for me and "the amber strands of gold that nestle upon your Devinne head." he says im really creep-ed out and confused and my boyfriend dose know and he is just as confused. my boyfriend and his best friend (the guy) are gonna met up juring the week and see whats going on. but i think the only way he'll hear it is from on facebook so help with that i know i need to be polite