hi seesaw!

I've had crushes on my online friends before, I don't normally tell them anything unless they seem interested in me too. But that's just me
I don't see any harm in telling him if that's what you really want to do, the worst that can happen is him saying he doesn't want to become romantically involved or something, if he's as good of a friend as you say he is, he shouldn't end the friendship based on that

Good luck, seesaw
I hope that helped