Yeah, no, she's an abuser. Point blank. They always "turn" on you later, because they're busy love-bombing and making everything seem like rainbows and peaches at first. Otherwise they'd never get into a position where they can wrestle control away from you! I truly feel for you friend, it's awful to live with abuse and most of the time you lose sight of what "normal" even means anymore. The abuser and their allies (accidental or otherwise) get to define "normal" FOR you after a while.
I hope he's able to get away from her and keep their child safe so he can begin healing. Keeping a strong support network of friends and family is VITAL to this - every abuser on Earth uses isolation as their first and most powerful tactic for controlling their target's life. Isolated and lonely people become frightened people, and scared people are easier to control.
I'm glad you shared this story and shed some light on the abuse dynamics men can face in their heterosexual partnerships, as there are some subtle differences I'd never been aware of until you put them into context here. Best to you and best of luck to your friend!