I'm surprised that her vet didn't at least recommend an appetite stimulant if nothing else. There are several that can be tried. It could be, as your friend suggested, that Max has lost his sense of smell due to a sinus infection. My Coco Puff lost his hearing due to that and he really didn't have any outstanding symptoms before then. (He has since regained partial hearing.) Another possibility is that Max may be having tooth or gum pain b/c he wouldn't eat food in his dish but ate it up when it was syringed into him. Of course, it's impossible to know unless/until your friend takes Max to another vet pronto. Whatever the case may be, if Max continues on this path, he will eventually just shut down. Do stress to your friend the importance of getting Max to another vet immediately. If s/he doesn't want to use Care Credit, perhaps your vet will work out payment arrangements for Max. Good luck w/this and please keep us posted.