This is WIFOM argument, but the times I remember grey as scum, I don't think he just rolls over and quits when scum. In recycled roles mafia, he was copped guilty and still tried making the argument he was framed. In Dark Crystal he argued his lynch into LYLO and won against supa.
Anytime he has been town and mislynched, he's shared the same sentiment as he is here: a willingness to die for the greater good. That said, times changes and people change. His flip is town could still be useful info.
I might suggest we milk the day phase instead of just lynching grey outright. Maybe get the rest of the claims. It's going to be pretty predictable one of me or drafter will likely die tonight, or one of the other town reads so the POE won't help a ton other than crossing off grey parrot. Also if mafia do have the investigative role, it might be useful to figure out who that is by pushing the rest of the claims today. if grey dies and flips town, we know who investigators are for next phase, that way we do have some POE info to work with.