I'm so sorry for your loss. When our dog passed it hit our family very hard. My son was 5 turning 6 and he had so many questions and feelings. We talked with him, hung up extra pictures of our girl and just did our best to remember her.
I'm so sorry for your loss. I'm sure he was a wonderful family dog and will be missed very much. It's difficult to lose a pet, even more difficult when it's sudden and unexpected.