Hello,
This is a difficult decision to make, but its good that you are looking ahead and trying to find the correct answers in order to give your dog the peace he needs one way or the other.
It sounds like he is in quite a bit of discomfort, so you may want to ask the vet about different medications that can be used. Since he refuses to take the medications you may want to consider liquid or injectable pain relief.
As for the eating, there are medications that can increase his appetite, the problem is if he refuses to take them then your in the same boat.
The same issue with diarrhea, there are medications, but he will likely refuse to take them.
The fact is he is a much older dog, and while you may be able to control these conditions by forcing the medications the reality is these conditions are only going to worsen over time and eventually new symptoms will start. 15 years is a lot for a Yorkie, so even if you can control his symptoms for a few weeks/months the reality is before long you will be back at the vets office looking for ways to curb his pain or mask his symptoms. The problem is his age is not curable, so at this point all you can do is try and mask his symptoms until the time comes when he passes.
Your questions to the Vet should be pretty point blank and honest.
Is any of the conditions he has curable?
Are they going to get worse over time?
If yes, what can be done to slow this, and how much additional time would be achieved by doing this?:
What does the vet think his quality of life is at this point?
What his quality of life will be in 3-6 months?
Let your vet know what you are considering, your vet should be your partner in the decision process and can help you better understand where he is at on the dogs path of life and where he will be in 6 months.
Then I would suggest asking yourself these questions:
Am I keeping onto him because of how I feel, or because I am confident that his quality of life is good?
How is his quality of life? (Keep in mind that dogs live for 3 basic things. 1. Play 2. Food 3. Loyalty)
If his quality of life is gone, can it return?
Am I making the best choice for my dogs needs?
I know it is a difficult situation to be in. You love your dog and the last thing you want to do is give up on him. But the reality is he needs you to do what is best for him, and sometimes that means helping him have a painless and easy passing.
I wish you the best and if you need anything or just want to talk please let me know.
Walter
Breeder
Breeder and pet health consultant. Have spent a number of years with dog rescue, training and health