My 2 cents: stress for an already-stressed import does matter. Personally, I'd first try one of those mail-in tests rather than a vet visit to see if you can get him healthier,
stronger, & eating for a while first & put off a vet visit until he is much more stable & can better handle it. I've used both Panacur & Flagyl in the past, & both seem
quite safe. They also usually improve the appetite, and that's a real "win".