fukd up b**** asked my friend the nicest guy ever out

i feel terrible for my best friend. he's in love with this girl and she's the worst to pick. obviously. i don't know what to say. and they are long distancing which means they have NEVER MET IN PERSON! she asked him out. pretty much she'll ask anyone out. idk how to tell him he's gonna get hurt real bad. i mean i been friends with him since eighth grade and i care a LOT. i dont want to make it seem as if i jealous (which im not who'd be jealous of a wh***?) or that i dont want him to be happy. which i do i want him to be as happy as the energizer bunny.