When should I set my dog free.?

I am so sorry for your precious baby,though it does sound like it is time to say goodbye,cause my answer is if they stop eating because of a illness they are feeling really awful and throwing up and diarriah is just as bad as not eating.I actually just had a neibour put her 11 year old dog down from stomach cancer and she coulnt keep anything down either ,and had no life left in her.I feel it is quality of life, not quantity.