advice r.e settlement after ending civil partnership

[MatchsticksForMyEyes]

My sister has just separated from her civil partner of 5 years. Her ex has a DD 14 from her marriage, but they haven't any children together. Currently my Dsis is expected to pay all the mortgage and a loan for a new kitchen that was in her name only.
She is trying to process a legal aid application, but is clueless about the finance side of things. Her ex has mental health issues and claims DLA for this.
Does anyone know how things work after ending a civil partnership? Will they divide their assets equally or will my sister be expected to support her partner, who claims she is unable to work? If this is the case, my sister continuing to pay off a mortgage and 10k worth of credit card debt, much of which her ex took out in my Dsis's name will mean she will never be able to afford her own place.

I would suggest that she talks to the CAB or book an advisory session with a solicitor. Some solicitors will offer a free half-hour and that can be enough to understand the basics. The way it works with divorce is that the marital assets are usually split 50/50. There are some concessions for any children involving the marital home. Children of the marriage are expected to be reasonably supported financially by the non-resident parent - which presumably is the natural father rather than your sister. Spouses are not automatically entitled to financial support unless they can demonstrate that, for example, they have given up lucrative careers to support their partner or that their lifestyle will radically suffer without help.

Debts that are in your sister's name, regardless of who took them out, are unfortunately the responsibility of your sister.

My sister was awarded maintenance for her DD when she divorced although she was married to the DD's stepfather, not the bio father. The bio father wasn't involved and my sister and the stepfather only got married when the DD was 6, but the court ruled that her DD was a child of the marriage as he'd been supporting the DD as his own for five years so he should continue to do so. DSis also has a MH diagnosis and got spousal maintenance. Her solicitor showed that her earning capacity as a result of her health problems meant that she wouldn't be able to support herself without help from her exH.