Is he trying to pull a fast one ?

[4seasons]

My friend , who is almost 60 lives with her grown up son . Her husband of 20+ years has moved out ... ostensibly to care for his ill father. She only works part time as she gave up a good job for one with hours to suit caring for her son. Her son isn’t ill/ disabled but struggles with everyday life and has lost his part time job due to Covid. Her husband is now pushing for a legal separation and says that if she doesn’t agree he will divorce her , stop paying his part of the mortgage and will go after the majority of her pension. I’ve told her that the courts will make these decisions, not him. He is a bully and she is obviously scared of him. She hasn’t confided in me about any possible DV. I’m very suspicious about his motives for wanting a separation as opposed to a divorce and have been wracking my brains about this. Can anyone help / suggest why he is pushing for this ?

I recommend that her son goes to dr and diagnosed with what ever he struggles with . He apply for benefits if he can and your freind become his carer. She tell her dr what is happening to her son her ( giving up work to care for son ) stuff with husband.
Then she goes for solicitors and get a divorce.

Is she due to inherit at some point, so he thinks if he's "only" separated he's in with a chance there?

Will he inherit anything when/if his father dies? Maybe he's trying to protect that? Maybe he's planning on early retirement and doesn't want to share his pension?
She really needs to see a solicitor for advice and also contact the benefits office to see if she and her son can get any financial help.

She needs legal advice.