Maybe just try giving him a drop or 2 every time you put it in his mouth. If you do end up trying it I would put as much protein and nutrients into his water as what I could. I've recommended this 3 times in the past couple of days and I'm about to make it 4. Silver Shield is an awsome infection...
You may have to give him some of his water through a syringe. Has he been eating? You could try floating some of his favorite treats on top of the water to entice him to drink. And I'm very sorry about what happened! :(