This is a moving story, @gabmr. The young boy tries to help the deceased girl. His family believes his story, and tries to help him. The time machine is actually more believable because the family cannot return to the present. Also, the story has a mixed ending. Happy because the dog is saved, and sad because the girl cannot be saved.
The fact that there are unanswered questions at the end actually reinforces the credibility of the tale.
Nicely done, @gabmr
Thanks for your comment and support. I tried to come up with an appealing story :)