Jee-sus. Why you gotta do him like that?
That’s not to say guys and girls can’t be friends. Opposite sexes can absolutely maintain a friendship as long as one party has no desire for anything more.
But the “gay best friend who isn’t gay” thing is just a weird move. Maybe it’s an inside joke? There’s no way Keith thinks it’s funny, though. I can see this girl now, “Oh, Keith, you’re so sweet and funny and you always help me pick out the best outfits… you’re like my gay best friend!” And Keith just stands there and forces a laugh while crying on the inside.