Alrighty, well, Pro Ears Promag Gold have a NRR of 33, which is as high as you can get in hearing protection.
They're big, and some folks have stock cheekweld issues with bulky muffs. It doesn't bother me with the ones I've used but I've never used that exact set.
The absolute best you could do in terms of protection would be those or some other pair with a NRR of 33 and wear a pair of foam plugs under them. I do that all the time. The volume boost of the muffs more than compensates for the foam plugs, so you can still here better than unprotected ears, but the total NRR is higher than either of them alone. You're going to pay high $200 range for those.
If he'd rather wear a hat to keep his ears warm or have the option of not having overheated ears in warmer weather, the Walker's Digital "Behind the Ear" style are very, very good. They even make some that have a wireless connection to two-way radios. There's a cord that plugs into the radio but it's wireless to the ear piece. Their downside is price. They're going to run $225 or more EACH, which means $450 for both sides and the NRR is quite a bit lower than you'd get with the first combination.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.