You must have read the same article I did about Greenland's native hunters taking polar bears with .223 ball ammo. They just sneak up and place the shot in the right place in the back of the head. They don't want to waste an ounce of anything edible or useful.
I don't know how that particular brake will do for that chambering? The only brake I've got personal experience with came on a 30-06 A-bolt I bought years ago, and the only reason I got that one was curiosity about how well its micrometer adjustment would really tune the barrel to group particular loads? It actually seems to work in that regard. People on either side of your position on the line complain about the muzzle blast, but of course recoil isn't really a problem with or without it.
The idea of a fixed brake usually causes me to have Harry's reaction. Professional hunters groan when tyros show up in Africa with a 460 Weatherby they need sighted-in because they've never fired it. (Harry, can you believe someone would drop 20-50K$ on a Safari and go without even knowing whether they could use their equipment? Apparently they do. There may really be such a thing as having too much money, after all.) On the other hand, having been privileged in the past to visit Jeff Cooper's armory and hold and snap the trigger on "Baby", his .460 G&A, and heard from him how it corrected the failure of another competent hunter's .375 H&H to stop a buffalo, I am not convinced there is never
a reason for a truly heavy gun. It is just adding the weight of a muzzle brake seems to me contrary to Cooper's concepts of "handiness" and speedy target acquisition in snap shooting.
Nonetheless, I took a look at Holland's web site, and that gave me a different perspective on this particular gadget. The appeal to me is not recoil relief, but Holland's claim to stop muzzle rise so thoroughly you can see your shot kick up dust when sighting-in or see its immediate effect on game. That might prove useful. The side ports are huge, so you won't have a problem venting a large gas volume the way a round-hole brake like my Browning tuner would have. Based on that, I'd say it's worth a try for curiosity's sake, provided it can be undone if it turns out the weight is a nuisance. You should call and speak to Holland and get their two-cents-worth and answers to any technical concerns? (541) 439-5155. I'd particularly inquire whether they can guarantee such complete vertical muzzle rise suppression with what you are chambering? Without that, I would advise the client with bursitis to get a Past recoil shield
and keep his muzzle light and pointable for surprise encounters with dangerous game.