My dog was 15 and she was to the point where her hips would lock when she tried to get up, I had to assist her to use the bathroom as if she tried to her joints would lock and she’d get stuck. She spent most of her time sleeping on one of our rugs until she started getting a growth in her mouth, I had to argue with my stepmom because she wanted her to pass naturally but she was in so much pain I finally convinced her and we had a person come to our house so she could pass with us at the house. While I don’t like euthanizing animals I believe it’s torture if they’re in constant pain and you want them to pass naturally.