Maybe dude needs some glasses. I had a helper that thought his work looked acceptable when it didn’t. I also thought he was just dumb and couldn’t read a tape. Turns out he just needed a pair of glasses.
I literally have a helper right now with that issue.
I really don't bust his balls too much about it though. Just give him tasks that suits his situation.
Thing is he's one of the best help I've ever had. He's retired navy so I go easy on him because he doesn't need this job and can tell me to piss off any time. Just works to keep busy and have extra pocket jingle.
But he's reliable, good work ethic, follows directions, and doesn't complain. Keeps me moving forward and cleans up behind me, touch up, cove base, transitions..... Just can't drive and do the fussy work.