settlement on separation

My friend is a cohabitee male in his sixties who has lived with his late 30s partner for 10years. They have 2 children aged 8 and 6. His partner has requested a separation saying she feels the age difference is showing and she wants her independence. My friend although not initiating this realises that this is what she wants. He has always been fully involved with the children and wishes for it to remain so. He had in place plans for retirement for 6 months time to become the caregiver and allow her to seek work if she (as she stated) wanted.
However the negotiations have become fraught. My friend acknowledges his responsibilities and wishes to pay maintenance for the children under CSM rules and agrees to pay for a car house and furnishings to support them until the youngest is 18. The partner has made no financial contribution to the house or any of his assets and is not on the deeds of his property. The girlfriend says she wants a clean split with money and she will move away and live in a council house. I do not see how she can get a council house if he will fund a property. He is also concerned that a lump sum settlement would be wasted and she would revert again for a settlement in the future whilst also removing the children to prevent him gaining regular access. As the partner with the funds he can see no reason why she will not protract the argument as she will receive legal aid and all costs seem to be borne by him. Could others in similar situations offer advice or some legal person explain her status if she declines a reasonable settlement (wishing to be independent) and limits access,Can she legally request a financial settlement like this

Thank you

Sounds like they're not married. Is this correct?

yes they are not married. they have lived together for 10years
She is getting increasingly aggressive in her manner. she says she feels financially trapped although he has offered to buy a property etc. She says this is mental cruelty.
If however he gave her a lump settlement as she seems to be requesting she has herself a poor credit risk history and could come again and again requiring support. My friend would rather provide the funding for a house but not in her name either his or a trust.
She is also saying that she will move away and so limit access. Can she do this?

As they are not married, he doesn’t have to give her anything. He will just have to pay child maintenance at CMS rate.

His understanding was that he has to ensure a roof over their heads and that she could also claim some finance through the childrens act. She appears to have all the say re the children and also wants money even though no financial input.
solicitors are not giving great guidance -just say go to mediation if you cannot get an agreement.