Yeah I’d bump him down in caliber for sure. As far as reducing recoil, I think a single shot, even with the lighter loads may still produce a bit of kick. I bought a pump action .270 for me and the wife to hunt with. Recoil pad on the stock and reduced recoil loads made it so she didn’t get beat up by it. Still has some kick to it though. I’d think an AR platform in something like 300 blackout or 6.5 Grendel would be a good option. I’ve only read about the 6.5 so maybe someone with experience can chime in.