i could see him being sort of an on-call reaper for a situation like that. maybe if your guy doesn't have enough reapers show up (are call ins a thing in the supernatural world?) he could call up jay and be like "yeah i'm going to need someone to come clean up this mess since glen didn't show up...again". he'd probably just roll his eyes and agree just so no one's soul gets stuck in their body after their death. jay's sort of a protective person so he might not be in the best mood if there's a particularly young or terrified victim to reap but it's gotta be done by someone. he could also muscle out some bodies for disposal but we're gonna have to find some brains for that operation because at that point jay will most likely be checked out - especially if the reaped soul refuses to cross over and he has to drag not only the body but the actual soul around all night as well.