Good girly Zoom for looking after him.
So sorry he's poorly, (((((((((((((((((Hugs)))))))))))))) for you and <<<<<<<<<<<Vibes>>>>>>>>>>> for Monty!
Bucket loads of HHO <<<vibes>>> for Monty, all fingers and toes crossed, I hope you get the results/answers you need and he recovers.
OP said he deteriorated last night and vet wasn't coming out until this afternoon. Does seem a long time for what sounds like a hideous thing to happen.