He isn't going to be shooting anywhere near 300 fps. The arrow alone will weigh in at about 410 grains with a 100 grain tip (assuming a 27 inch arrow with 4" vanes).

Then add the things such a a peep sight, loop, string silencers, kisser button and if he has a shorter draw length than 30 inches and 300 fps is a far cry.

Post his exact set up (everything) and I bet he is right where he should be.