Did he have to get a doctors permit to hunt with it? I don't know if thats a state law anymore but it used to be. I remember my dad trying to get a doctors note so he could buy one and hunt with it. It probably isn't in existence anymore but you used to have to get proof that you were unable to hunt with a standard bow in order to hunt with a crossbow. Here's the law as of 2008 but im not sure if thats still intact now. Just a bit of info. Your in Idabel and honestly I wouldn't worry about it if you didn't know about the law before now. I seriously doubt any game warden is going to ask what you killed the animal in question with. That law just concerns hunting with a crowssbow not purchasing one so it shouldn't matter either way.
The Wildlife Department no longer issues crossbow permits.
Hunters who have a permanent disability to the extent that they cannot use a conventional longbow, as certified by a physician licensed to practice in Oklahoma or bordering state, may hunt with a crossbow.
A person who qualifies to use a crossbow shall have in their possession while in the field written evidence of such certification.
You will need to go to and download a form that your doctor can fill out and then carry that form with you in the field, while hunting with your crossbow.
Hunters with existing permits (lifetime crossbow permit) may use it for as long as the hunter hunts.
You can also carry your expired crossbow permit as proof of permanent disability instead of a new letter (since you had to have proof to get the crossbow license in the first place).