That's a tough one, I quickly reviewed Hawaii's "rabies free" policy. I'm sure you've checked extended family and any options that way. I'd offer to watch him, being a past owner of two old dogs myself, but my schedule over the summer months is gone a lot. Dogs and people like their routines. Don't know if state vets on the Hawaii end have any room for interpretation, based on your dog's health history.
Good luck,
jh
