This seems to be case of territorial aggression in my opinion. Several factors seem to be an issue.

1) The dog was a rescue covered in cigarette burns. So it had a history of human abuse,the extent of which was impossible to know.

2) She brought a new puppy home and did not properly introduce the dogs to each other.

3) She let the dog sleep on the bed with her. This seems ok for some dogs but could also be a sign that the dog did not regard her as the alpha in the relationship.

4) Her friend told her dog to get down. With the new puppy there her pitbull was already on edge. So he lunged at her friend, saying, “you are not the boss here. I am!”.

5) it is shocking that the woman didn’t seem to pick up on the warning signs that her pitbull was having issues. I don’t believe the behavior just came from now where.

6) It seems the dog attacking her was a re-direct because he couldn’t get to the friend (target).

7) She noted that Hercules was beginning to display “food aggression”. Another sign that maybe a new puppy was not prudent.

It is regrettable that the woman went through this situation. I think there is more to know about this story.