Illness/Sickness: Please help me determine what went wrong

Hi I've been sent to this site multiple times by google whenever I had a question about my axolotl or tiger salamander and it was very helpful. I have had my axolotl for close to two years now and she was given to me as an adult.

I had left town for a few days and had my brother take care of my salamanders while I was away. I came home today to find my axolotl covered in what looked like white shedding, I'll try to put up pics. The white stuff would flake off when she moved around but, she was also very lethargic and would not eat. I looked on the site and online and there was some information about shedding in axolotls and how it was not a too big an issue.

I just came home from work and I think she is dead she is not moving at all, her gills have shrunken down to near nothing and are mostly white or pale. Her limbs are red with some blood pooled under the surface of some toes. And the area just around her gills looks like a moldy gray.

I'm sorry if this is morbid, but this was my first axolotl and I would like to know what could have been the cause of death so I can try to prevent it if I get another, which isn't always the easiest thing in Hawaii.

I believe when an axolotl is dead they float belly up? but I'm not totally sure
The best bet without a picture is a fungy infection
It's treatable with salt baths and fridging, this website is full of tutorials on how to do that

In the future, you might want to keep a closer eye to water chemicals (NO2 / NO3 / Chlorate / Ammonia / PH) are by far the most important
You can search on this website for "nitrogen cycle"

To give more specific information I'll need a picture of the axolotl, preferrably a picture of your tank setup and some water value's

I'm hoping it's not to late but that might be false hope...
If it shown any sign of life, pop him in the fridge right away