There is so much marketing bs floating around right now it is insane. Obviously, heavy, slow, cut on contact works. Personally, I want as much danger space as I can get. If I need better penetration I will switch to a smaller more pointy broadhead. Broadhead sharpness is the #1 limiter of penetration.300 is light but around 400 isn’t. Guys don’t shoot 300 for penetration problems, it’s more of ridiculous nightmare for tuning. Which, will cause major penetration issues as well. I would have him shoot a 500 axis and a two blade coc. Magnus stingers or a Simmons Mako would be my choice.
My experience is the opposite of what is popular today. I won't argue elk, bear, etc. I was a tournament 3-d shooter first. No one in my family was a deer hunter so the learning curve was long. My first whitetail was shot at 60 lbs with a 300 grain arrow and a 75 grain rocket miniblaster which was a 3 blade 1.75" cut mechanical. The shot was 52 yards and broadside. It was a complete pass through. This was repeated many times. The only thing I did that was unconventional for the time was to take the brand new broadhead blades and sharpen then RAZOR sharp.
My current set-up is a 360 grain arrow at 74 pounds with the same broadhead. Within the constraints of normal hunting distances, 50 yards and under, there have been zero issues.
I am NOT advocating mechanical heads for low poundage setups, but the heavy arrow craze is EXTREMELY overblown. Today's bows are quieter, smoother, and more shootable than years ago and having a margin of error for range is very valuable.