It looks like Chaplin's struggling a bit there Dale. His urine's extremely dilute and he's anaemic. His numbers haven't come down as much as you'd hope. It's worth giving him a chance to see how he does with daily sub qs (maybe even twice daily). And antiacid, anti nausea and an appetite stimulant. If you only got a few months of good quality life it would be worth it, and there's always cats who beat the odds and outlive expectations.
Dale, have you tried joining and discussing your kitty's labs with this support group? There are some very knowledgable people who can help you understand what's going on support groups.io Group
Excessive thirst can also be a sign for IBD, which my Winston has. He ate very well; however continued to lose weight, became lethargic and had excessive thirst. He is now on Predilisone as well as chlorambucil and is responding to that!
KIdney failure would make his breath have a sticky sweet smell
throid would make him gain or loose weight and he'd always be hungry and either be over active or sluggish
UTI would make him not use the litter box, because urinating burns he'd be looking for something soft to piddle on, like a blanket, your bed ect.
Amoxicillin is an anti biotic and if there was no infection as suggested by the blood work it wouldn't do him any good
Metronidazole is for loose stools