I am sorry that you and your daughters have had a difficult day. Still..it is very good that you are sho
wing your son your feelings...this is how he is going to learn about emotions and how important it is to express those feelings.
All of you are grieving. A member of your family has died and it is important to grieve that loss. Here is a very good book for you to get that will help all of the family:
When Your Pet Dies: A Guide to Mourning, Remembering and Healing Alan D. Wolfelt PhD
This book costs $9.95.
I did see that same $130 book...I will give you the website of Centering Corporation. They have Thumpy's Story in stock at $9.00
As I wrote earlier, you are bound to feel like a bad parent here. However, the truth is that you could not have predicted what was going to happen. And..neither could your son. He did not understand the consequences of his behavior. He loved the dog. And he will miss the dog terribly. Like you and your daughters, he will need loving support to understand that he is not a bad boy. Rather he is a curious boy and had no intention of harming the dog.
I am sorry that you are feeling such pain. Finding ways to remember her and to talk about her will help with the healing as it is by remembering rather than forgetting that we work through our grief.
Please let me know if I can be of further assistance to you and your family.