So very hard to answer. I'm even having trouble finding the "right" words. Knowing in advance might give us time to prepare, but how do you really prepare. I haven't had to face it with my hounds, but I have been faced the loss of treasured cats. In all three cases, I had advance warning, but watching them go down hill was hard - especially with K.C. By the time I decided to help him over, the cancer had left him a mere shadow of himself. On the other hand, there was the chance to say goodbye. So, in I end up where I started - I just don't know.
I'm sorry for your loss - pretty inadequate words.