Has she spoken to Women's Aid to talk through her fears and get advice on what will and won't happen.
Has he told her social services will take the children away if she tells anyone what he does to her? Or if she called the police. Just wondering, because that's a very specific fear for her to have, and conveniently benefits the man abusing her for her to believe that.
If she's proactive in asking for help, taking up offers of support, and removing him from the house and their lives then nobody would have any reason to intervene other than to provide support. They are more likely to get involved if she doesn't get him to leave and doesn't call the police when she needs them.
If she calls the police to get him to leave, everybody will bend over backwards to support her in protecting them all (including herself).
Your friend might find the Freedom Programme helpful to get some clarity and understand what's been going on. (Freedomprogramme.co.uk) If she does the course, it's 12 weeks, 2 hrs per week, in a small group. There is no standing up in front of everyone to share your life story! She can just sit and listen.
I was petrified about going when it was me, but it was such a supportive environment I started looking forward to it, and missed it afterwards.
Oh, and I didn't get around to answering your original question, because this is textbook abuse. Nothing described in the OP is anything other than abuse. It sure as hell ain't concern.
I hope your friend is able to get him out of her life so she can start building the happy future she deserves - and will find once he's gone.