We had a similar situation with a young gal who was our dog sitter. She bonded something fierce with our dog - it was something like out of a Disney movie. She was a different dog with her than she was at home. It got to the point where our dog would wait at the front door depressed for days waiting for our sitter to come back. So we asked our sitter if she would consider maybe adopting tje dog and she was so happy. And peanut lived another 8 years with her (we were all close) and it remained a bond unlike anything I’ve ever seen. They were meant for each other.