If I was in your position, I would not only prevent him from BOW hunting on your land, I would prevent him from GUN hunting on your land.
My dad taught me that hunting is a "one shot, one kill" mentality. Gun or bow. I had to use a break action for the first two years that I hunted. The only way to get a deer with a break action is with practice, patience, hard work, and skill. No short cuts. Bow hunting forces you into this mentality but if you learn it early than its just second nature. I'm not tooting my own horn but if everyone learns to shoot this way, we would have a lot fewer anti's out there.
I agree with the other posters that we owe it to the deer to make clean ethical kills. Ask your other hunter if he would like an arrow through his gut and then die 12 hours later. Not a fun picture.