He's a legit black belt. But he's also a small size 54 years old guy
Good, big, athletic blue belts could give him trouble or at least make him work
I'm an average blue belt and my coach is smaller than me and he's also old. He always end up subbing me but I make him work
At blue belt most guys have some stuff that they are good at. I have a very good half guard / RDLR game against guys who try knee slides. It's not unbeatable, it's not bullet proof but I make purple belts, brown belts and black belts work a lot in those circumstances. Even more if they are older, weaker or smaller guys.