First, condolences on your loss. It is a necessary part of the whole equation.
Second, I am glad to see you taking the boys with you. I hope they learned it is OK to be sad when bad things happen, that death is always a part of life and most importantly, just because the decision is difficult doesn't relieve one of the responsibility to make it.
Having been in the animal training business, a dog handler for many years and in rescue (over several hundred dogs) I have made that trip more times then I care to remember. Some things get easier, that is certainly not one of them.
Joe
JC Custom WoodWorks
For best results, try not to do anything stupid.
"So this is how liberty dies...with thunderous applause." - Padmé Amidala "Star Wars III: The Revenge of the Sith"