M.P.
I suggest this is normal for most kids even those without an asd diagnosis.
He's focusing on the most exciting part of the story. We all go for action movies. He is also trying out different ways that people relate to each other. Once he's mastered this he'll move on to a different interest.
The incidents you decribe are harmless. Even having the alligator get your finger. I've had dozens of kids play that game with me. He's using his imagination. Thats a good thing.
Not reading certain words is not helpful. He will hear them with other people. He also likely knows you're skipping them. Best to read them and be open to ttalking about the action. A part of the conversation can be a reminder that this is not real. It's just s story. You can talk about how we don't treat people this way. It is fun to imagine such things but not to do them. Be casual. Allow him his fantasy and then enlarge on it. It's great fun to use imagination. Ask him questions about other parts of the story.
If this continues to concern you talk to your son's professional team. I suggest reading about child development will help.