why did my dog die?

Question
our dog of 13 years recently died.   She was diagnosed with kidney and liver cancer a few months ago.  She had stopped eating,  I found a food that contain mostly protein and we mixed it with her normally food. She started eating 3+ bowls a day.  She was very thirsty so I would ass pedialight to her water (vet said it was ok).  She was doing great, no more day days.  So what happened?  We found her with a small pool of blood my her mouth.  She was out of her house, very very weird>  She had to stay in the garage when we were gone (was having urine accidents in the house it no one was home).  She had a house on foam installation,  4 very thick blankets and a heavy comforter.  She never left her house unless she had to go to the bathroom or was coming gin the house.  She was lying on her side in front of it on cold concrete, WHY?   She need some type of closer so please help.  Did her cancer finally get to her?

Answer
I would have to say that her cancer finally got to her. This question is rather confusing to me- you say she needs some sort of closure but who is she? And what does this mean-"She was doing great, no more day days." I am confused by that sentence.

High protein foods are the worst thing that can be fed to an older dog or a dog with compromised kidneys. The kidneys have to filter all of that protein and when they are not doing well they cannot filter it and it builds up in the bloodstream.

Once that happens the toxins build up and causes burns in the mouth, seizures, and disorientation. Finally the dog will succumb to the poisons.

Many dogs will move out of the comfort of something warm when they are dying and will try to hide before they die. I am sorry for your loss, no matte how we lose them it's hard. 13 yrs is a good long life for a dog. She lived and full and loved life.

You will miss her but remember her love for you and that will bring you comfort. I hope you can find some peace in the coming days.