I'd agree about the form problem, a good proshop should be able to straighten out your friend, the quicker the better.
Who cares wha others use, why ban anything? Very stupid idea, trying to "ban" something. Deer are so thick in most areas you're tripping over them, they have special rifle and blackpowder seasons in early fall, if you think crossbows are going to "hurt" "your" season, you're a little dense. Bag limits will only get more liberal as more land is off limits, and populations increase. Who cares about the equipment used?
That being said, I've killed a dozen deer in the past few years with a compound, I could have killed 5 or 6 more with a recurve where I didn't have to worry about enough light to see the pins on overcast mornings and evenings.
As the average deer is shot at about 15yds, a chip shot with ANY equipment, a recurve or longbow is much deadlier in the thick woods the vast majority of hunters encounter, and makes it a lot easier to put meat on the table. Perhaps they should be outlawed?
I can pick up a recurve or longbow I've never shot and kill a deer every time at 15 yards after a couple practice sessions, are THEY too easy?

"In heaven, even the fish have antlers"