The reality for the poor little guy is that he needs a 100% water change daily for 10 days, a heater, antibiotics, medicated-soaked blood worms and a dark room to recoup. Without the proper care at this point I don't see how he could make it. It sounds like he has an internal bacterial infection which is causing severe SBD. I'm not sure what the owner is saying by stating "something is wrong with our water". Sounds like a simple lack of fish keeping experience. Usually you can just logon to your local water district and take a look at the general parameters (however, you need to be a water chemist to understand all of it! Ha!) But on a serious note, I'm sure a good water conditioner like Prime could just take care of it. I'll keep my fingers crossed that she'll give the little guy to you before he swims his way to the Rainbow Bridge.