I think no
Even though Sehun ever mentioned Luhan in interview and talked about how close he is with Luhan (you can search the video on youtube, it was on MAMA era. seriously this is CUTE!) but all they said not too much like that.
Yes^^ HunHan just like bestfriends each other, brothership, which means Luhan is a good hyung for Sehun, and otherwise.