How did she die?

So our dog Zoe has had a rough few months. It started well over three years ago, when she got a lump on her jaw. It was removed, but grew back. This happened 3 times before the vet referred us to a serious veterinary surgeon. The latter removed part of Zoe's lower jaw in an operation that took over 6 hours. It cost a small fortune. And afterward, I am not sure Zoe was happy we did it. It took many days for her to recover, and she never felt fully comfortable playing with her young pal, Gracie, again.
Well, Zoe did make it through that, but it was the beginning of the 'lumpy years'. Big fatty tumors here and there; small fleshy ones every now and then. A couple of these small fleshy ones were removed, including one last April, a few weeks shy of Zoe's 13th birthday. The vet was dubious about her ability to withstand the anesthesia, but she did. This probably in large part to our vet's amazing skill and prowess. And Zoe spent many more weeks being happy and a wild ball chaser.
Zoe had lost a few steps in the last year, but still went wild at the country house, where for hours on end she would bark at us to throw her ball.
Then this summer hit. She started to atrophy in weird places; she started losing her balance. And, she became increasingly incontinent.
As the summer wore on, it was clear she was loosing ground. When we returned from our vacation in Iceland in late August, Zoe was tired, and had bouts of laboured breathing. She could no longer get herself up. We helped her stand several times a day, and we took her outside for her needs. A few times we missed on getting her out in time, but followed up with a bath that seemed much appreciated by her.
But then, late last week she had very tough nights. She couldn't breathe well, she stopped eating all her food. And she no longer wanted her daily walk. All signs that the earthly treats were losing their appeal for her.
I knew it was time that Zoe leave our lives. I didn't like the idea, but what could we do? Watch her suffer endlessly? Our former dog, Nike, live to nearly 16. And she was in very difficult straits at the end. Our vet told us then: 80% of dogs die through euthanasia. Wow. So veterinary medicine is so advanced it keeps them alive... but sometimes too long. I knew the chances were not good that Zoe would die on her own. I took the decision to make the fateful appointment with the vet for Friday the 3rd of September. But it was not to be. I was overruled. Zoe should go to the country one last time according to other family members.
Although it is true she seemed to perk up and enjoy her time in the country, she was not herself. She had trouble moving and doing what she liked. She chased a few balls, but that was it. Upon our return, the decline picked up where it left off. Since Abigail's dad was out of the country, it was up to me by myself to take Zoe to the vet to relieve her pain and suffering.
So I did. Abigail's older sister, Emily, courageously volunteered to come with me. We cried over Zoe in front of our benevolent vet. He left us as much time with her as we wanted. She had her first medication to relax her, and she did, right on my lap. We stroked her face and told her how much we loved her. She slept peacefully when we left; the vet assured us he would end her life humanely.
When Nike was euthanized 6 years ago, Emily was told that she had died at the vet's office. Emily took this at face value. It was technically true, but we didn't tell her that the vet had 'helped her along' at our request. We did tell her recently, though. She took it well.
When Emily and I returned from the vet, Abigail asked, 'Where is Zoe?' I told her that Zoe had died at the vet's office. I was sure it was good enough -- it had been for her big sister -- but it wasn't. Abigail persisted, 'How did she die?' Ah... what to say.
Well, I told her the closest thing to the truth that I could: she was very sick. She died of her illness, which had become too much for her. One day I will give a more precise, and truthful, answer to Abigail. For now, Abigail tells everyone that Zoe died. Emily and I keep to ourselves about it, and discuss Zoe's death in low tones between ourselves. It was a shared experience for us two. Abigail doesn't miss Zoe in the obvious way -- Zoe was, after all, very old and difficult for Abigail to handle well. She had missed Zoe's young and wild days. Abigail is more in tune with Gracie, in whom she finds a soul mate. But Abigail still discusses Zoe's death with the confused fascination of the young.
Zoe will fade into the family history, with the stories about her exploits taking on mythical proportions. Isaac Bashevis Singer said it best with regards to the passing of loved ones: "The living die, so the dead can live." Zoe is still alive in my heart, but she is sadly lacking in our home.