This logline is shorter and reads faster but still describes a vague and un clear plot.
I think I may have not been clear about the need for a cause and effect relationship between the inciting incident and the goal.
After Luke's adoptive parents, aunt Beru and uncle Owen, are killed by imperial troopers he must accompany a Jedi knight on a quest to join the rebellion and defeat the evil galactic empire.
Luke's goal is a clear cut derivative of his inciting incident which was a significant event none like any other he had experienced before that point.
However in your story finding his brother is not a direct derivative of the MC rescuing a dog. As a result the plot is fragmented between seemingly unrelated events therefore it fails to illustrate a dramatic spin from start to finish.
As previously mentioned if the goal is the brother the dog is an ally and unrelated to the plot and may not need to be in the logline.