I agree, its roots look pretty good. It looks like it has some algae or something on the media (I just dealt with this yesterday on a mini guy I picked up). If you can, maybe carefully take him out of his pot and have a look at his roots, maybe loosen up some of that sphag in the middle and then if he looks good and the media isn't too icky, leave him until he's done blooming. Otherwise, as Hannah said, repot but you might lose the current flowers. That said, if he's shooting out a new spike, he might bloom on that one.