Sorry, Bill, that is something i am dreading.
Here is Lucky, a Shephard Chow mix. Vera found Lucky in the shelter and worked with him for months to become her service dog. Lucky could alert her when her cortisol was low (medical alert], and could assist with her mobility. He saved her life at least once, probably more that she would not admit to. She has Addison's and if her cortisol goes too low, she could slip into a cona and die. Lucky would alert her and she would take her meds to bring up her levels. 2020 happened, and Lucky lost his socialization skills and became more protective, so he retired in 2022 from working (plus I work remote most days and can watch Vera too).
A few months ago, the vet found a tumor and he has cancer. We decided he doesn't need to go through the pain or surgery for maybe an extra year so we are giving him extra pets and butt scratches until the day he tells us he is done. I think we still have some time, but i fear I will be very sad soon.
Sorry for your loss.