If you are a new hire, I would say let it go and let the system do its job.

From what it sounds like, he is probably already a topic with the instructors and check airmen. If it were me, I would let it slide for a few months and then go back at talk to the instructor and get some feedback. I reserve pro-standards for stuff that guys do on the line and then it is almost a last resort.
In any event, sit on it for a little while before you decide what you need to do.

I can almost guarantee this guy is gonna talk smack about you to his friends/co-pilots because of his inability/slackness. Had it happen.