Child STILL Grieving Over Loss of Pet

[puprock97]

My 12 year old niece is still grieving over the loss of her childhood dog.
A few months before she was born, my sister bought a Labrador Retriever puppy for Casey(my niece)'s half brother. After Casey was born, Sherman (the dog) became more like Casey's dog. She did everything with him. They'd cuddle, he'd sleep in her room, she talked to him, etc. Even after Casey got a puppy of her own, she still always favored Sherman. She referred to him as her best friend. She called him "Ol' man". He was put to sleep on St. Patrick's Day of 2010, and Casey was devastated. She wouldn't talk to anyone at all. She wouldn't let anyone hug her, or try to comfort her. She'd stay in her room for the majority of the day. She cried a little, but she was mainly silent. The only time we'd actually see her was when she'd come down to grab photo albums (containing pictures of Sherman) and a little bit of food. Nowadays, Casey seems better, but still not 100%. Sherman had a small, thin silver chain necklace that he wore under his collar and ever since he died, Casey wears it. She refuses to take it off. She keeps pictures of Sherman everywhere. She has a picture of him that she puts in the drawer of her desk, one that is taped to the wall of her room, one in her wallet, and one that she keeps under her pillow. She keeps his old dog bed in her room (her current dog sleeps on it.). She has Sherman's collar, tons of pictures of him with her, his old toys, and his old brush in a box in her closet. She still has times where she pulls that box out, and she just takes out the toys and the pictures and looks at them for a while. She talks about him every chance that she gets. Her mother brought up the subject of getting another dog, and during every trip we've taken to the animal shelter, she always favors dogs that resemble Sherman.
She carries these two pictures with her :
http://i54.tinypic.com/2rpu0k6.jpg
http://i51.tinypic.com/153afk4.jpg
Is it normal for her to still be this attached to him?

[Kevin Kennedy, Ph.D.]

If her baseline functioning has changed it would warrant her parents' arranging an evaluation with a pediatric mental health professional.

[puprock97]

Because of the 2000 character limit, some things were left out. After Sherman was PTS, Casey became more reserved. She used to be wonderfully outgoing, and now she's become more of a loner.

[Kevin Kennedy, Ph.D.]

This was a major loss for her. As long as she is otherwise functioing well - i.e., socializing, doing well in school, behaving well in the family, having some recreational activities with peers - there really is nothing to worry about.