I have a poem that I wrote years ago when I lost a special cat. I will post it in another thread...
Reading what you wrote about Buster and Mandi brought tears...Animals are so loving and even though they do not understand death, they know that something is wrong. That their brother/sister is gone. Two years...And people say that animals don't have feelings...memories...Mandi grieved a long time...now she is running and playing with Buster once again...