Worst-case anticipated scenario is biking up in the Front Range foothills and having to get a mountain lion off his young daughter. My sense is that the Super Alaskan is the best choice; no doubt that if he hits it in the right place, it's going down. The .454 Casull is a good round for that and I like the snub. I'm recommending a front fannypack holster for him as well; so he can go from ease of biking to calm in shopping without having social issues arising amongst the hoplophobes.
Yes, correct that he's not a regular shooter. That's why I am recommending revolvers only; simple, no jamming worries under stress and powerful enough to do the job.
The .454 Casull is a good round for that and I like the snub. .454 is a huge, intimidating cartridge for a non-shooter, esp in a small-ish platform like the Ruger.
For Alaska, or Montana where 1000lb bears are common, maybe a good choice, but for a 120lb Cougar, a properly loaded 357 or .44 Magnum is PLENTY of gun.
.44 Mag is reasonably suitable for bears, properly loaded.
The .480/.454 is too much gun, too heavy, excessive recoil, for a non shooter concerned about relatively small predators.
JMO.