I have an American bully. He started watching over baby calves, then one of my neighbors was sick and he stayed at their house. Now a neighbor down the road lost her dad day before yesterday, and when he goes outside he goes to their house. Can you tell me why?
Your dog is not running away, he is visiting all of his friends.
If there is a risk of him getting run over by cars, abused by strangers, mingling with diseased dogs (eg, mange), or tangling with hostile wildlife, you may want to re-design his yard-space so that he cannot escape anymore.
As your dog is prone to wander, please make sure that he is microchipped, so he can be returned to you if he looses his way.