Very sorry to hear this, Yves, even more so as he was apparently of such great help to your wife. She must miss him terribly. Dogs can be such wonderful and comforting companions. Our oldest dog is 11 now. She was recently diagnosed with a heart disease and I can't bear to think of the time when she won't be with us anymore.
We've lost several pets. They mostly died of old age, but losingone is something I'll never get used to and it's always too soon. Go through your pictures, find the best one(s), have it printed and try to remember the many good times you've shared. It used to help me - in the end.