Sick chinchilla. Could really use some advice.

I got my chinchilla from a breeder back on April 17th. He was born on February 13th. Everything was great at first except for he has never drank much water. A couple weeks ago I noticed that he stopped drinking almost entirely and his poop started to get small and then he stopped pooping almost entirely. He went to the vet that day and they gave me critical care and said they didn't really know what was going on. Vet said to give him 10 ml a day I've been giving him about 12. 6 in the...

Sick chinchilla. Could really use some advice.