Daryl - the .50 Dragon claws by Sam Yang you can buy "air bolts" for. They also just released the .357/9mm AirBolt for the Sam Yang Recluse (the 9mm version of the Claw, basically). The .45 is called the 909 or Light Hunter. They are next for the AirBolt development so your friend will be able to get them soon.

They fire the arrows at like 450-500fps, here's a good video.

I've actually been curious how they'd go with arrows heavy enough for Jumbos.. if they can get the velocity then.. well, the Airbolts would make an elephant with an airgun possible! Not the safest of options of course, but doable..

https://m.youtube.com/watch?v=tl5F65ALB3I

https://m.youtube.com/watch?t=184s&v=ZH3FBOQK6oY

I'll be getting a Recluse for my next rifle, probably.