my brutus

[busterb12]

I have a german sheperd he is 14 yrs old, when he was
6mo. old he started to loose some hair I took him to the
vet. She thought right away it was mites or something really bad. She then did a biopsy on him she told me he suffered from allergies, she said I could put him down
he really wouldn't be a good dog. That was 131/2 yrs ago
We have done and purchased everything and anything
possible to make him so comfortable, now it is the hardest thing to think about putting him down he has lost his hearing and his back end is going out and today he stop eating for the first time, this is the saddest day in my life what should i do?