Popcorns mum... your story is heartbreaking in that you are having to deal with too much. It is more than just grief and guilt you are facing. We can all relate to loss, but then there are the circumstances of that loss. Each one is individual and personal. You trusted this person to care for Popcorn as you would have done. You did nothing wrong there. You had no reason in the world to believe your trust would be betrayed and you probably have many unanswered questions because of that. An answer to one question, why? just throws up another, and so there is no closure. Can I ask, and I understand if this is difficult to answer, how is your daughters dad dealing with this? Does he have any guilt or remorse? Does he still feel he did the right thing for Popcorn?
Grief and guilt takes you off somewhere where your imagination runs riot. I know I can't compare the loss of my Timothy with that of Popcorn, but I will never know how or why he died. So in my imagination he was begging me not to go and leave him, he died looking at the door waiting for me to come home and help him. Rabbits don't make sounds, but he was crying out for me, he didn't just lay down and fall asleep, he died in pain and not just pain, agonising pain. That's where I am and I'm stuck there forever. We humanise our furbabies and give them human thoughts and feelings and emotions because they are an extension of our children and that is all we know. It's doubtful that their little minds work that way.
I wish I could send you the words to give you and your daughter even a tiny bit of comfort. Like I say, you have too much to deal with all at once. Writing here is the next best thing to talking, so maybe it will help a little.
Sending you kind thoughts
" The pain I feel now is the happiness I had before. That's the deal" C.S. Lewis