If he's only 8 months into archery - it might as well be a different bow every time he picks it up.

I do it all the time to myself, and I'm a lot more than 8mos into archery. I have a couple Mathews bows and a Bowtech. One of my Mathews is set up for high wrist, the rest of my bows are all gripped for my shooting style - to heel the holy he11 out of them.

If I shoot the high wrist Mathews the way I shoot the rest, by heeling it, the POI will CONSISTENTLY be different. If I get in high wrist mode with it, then come back and thumb my Destroyer, it's POI will be CONSISTENTLY different.

I also flop back and forth between a wrist release and a T release, even throwing a back-tension in there (still not convinced I want to fully convert over for hunting). Changing between releases ends up changing my anchor point, and ends up changing my POI. Is it enough to notice at 30yrds? Eh, not really. Get out to 60, and it sure is.

So it could be the bow. Not saying it's not. But more often than not, unless there's some "injurous event" where the bow takes on some physical change, it's the indian, not the arrow. Or bow, in this case.