Jen, has the local shelter contacted a Himmy or Persian rescue organization about this guy? Is he in a no-kill shelter?

About the teeth ... Some of the Found Cats have had dental care in their double-digit years. I don't think that is as big a problem as a bad heart. What is the prognosis for this grade 3 to 5 murmur? In a human patient there is a big difference between grade 3 and grade 5 and I wonder if that is also true of a cat.

I think he could still have good years with a permanent foster or a caring adopter unless his heart is very, very bad. If the vet doesn't want to do his dental care without an ultrasound, I can Paypal something toward that. Will wait for your decision.