Hard to tell.
Sometimes it looks like he's putting his hands up or trying to stand up, only like the last 3-5 shots look like it should be stopped for me. In fact, half way through those shots I'm pretty sure he tries to grab one of his hands to stop the punching.
Could just be me, though.
It's not hard to tell. He was defending in the same way that Schaub was trying to pull Rothwell into his guard. That was mostly muscle memory.
He may not have been out stiff, but a referee is supposed to stop the fight when a fighter stops defending intelligently. And Zaromskis was just eating undefended shots. Horribly late stoppage.