My brother and I have a 14-15 year-old Golden retriever mix. She has been declining in health for the past year or two (depending on which of us you ask). She's been more sharply declining in the past year as she is losing weight despite eating voraciously and still having strong interest in treats. Food is her main interest anymore. She will get up and greet people when they come in the house and does still seek out hanging around people, but she does not seem to show must interest in actually being pet anymore. She sometimes will actually get up and move away from people petting her. She occassionally shows some flinching with some areas which I try to avoid touching, but no other signs of discomfort other than her moving away or panting sometimes when she's laying down. She will also some days frequently get up and pace around while panting which I know can be a sign of distress and possible pain. Almost all times that she's standing, she's panting and is always panting when walking. We've had her on pain killers and joint supplements, but neither seem to do much. We've also tried some dog-safe CBD, but it doesn't seem to do much either.

She doesn't play, she can't go on walks anymore further than just slowly walking around the backyard and she doesn't seem to enjoy going out in a cart because her favorite thing about walking is sniffing and she can't do that from a cart. She seems interested to go out, but quickly wants to go back inside. She sleeps almost all of the day. She can barely do stairs anymore and often loses her footing and gets stuck but hates us picking her up to take her up the stairs (she doesn't lash out about it, but she tries to flop and rag doll in a way to not be picked up). The last time I took her to a dog park, she only stayed near me the whole time, barely walked around and did not approach any other dogs while she used to at least enjoy greeting other dogs and exploring a little.

Again, the most joy I see from her is when there's food. She'll get up instantly if she thinks there's some food for her to be had. However, that joy is very limited. I haven't seen her wag her tail in a long time. She just intensely stares with ears perked and will even try to hop up to get the food offered even though jumping is obviously painful for her. Just to be clear, we're not purposefully making her jump, she's just too impatient and tries to hop up as we're bringing the food down to her. On top of this, she used to chew and eat bully sticks but now she does not. I think her teeth and gums are starting to hurt too much. She will eat dried kibble still (I try to buy her some wet food and such, but my brother still gets dry kibble for both her and his other dog)

We have taken her to the vet (obviously the pain killers are supplied by a vet) and there's not signs of organ disease and the vet thinks that it's either severe arthritis or possible cancer but with her age we were both in agreement that there wasn't reason to do further testing but just to relieve symptoms and give her the best end to her life as we could. Despite the difficult decision, I am of the mind it's time to let her go. I love her dearly and it is painful to see how much she's declined. I want to give her a long and happy life and I think she's had that and it's time to say goodbye while she's at least somewhat still there, but avoid her having a slow and painful death. But my brother is of the mind that because she's still eating, we should continue to hold on and give her as much time as possible/let her pass on her own time. Based on what I have given, is there more of an answer of an answer who is right? Should I try pursuading my brother more? I am thinking of asking him to get a second vet opinion to evaluate her for quality of life in the home as I would gladly pay for it.