I just cannot even imagine this happening and to have my daughter be the one to find one of my pups in this condition

My heartfelt sympathy goes out to you and your entire family at this very difficult time. What a tragic lose that you have been dealt in the passing of your little one.
Please keep up updated if you are able to find any answers to what happened. I have a thousand questions to ask you but this is not the appropriate place for my questions. Take comfort in knowing that you have the YT community to support you at this very sad time.