Thank you for your question
My name is Clare
I shall do my best to help you but I need some further information first
Were they married?
How much is the house worth and how much is outstanding on the mortgage?
What income do they each actually have?
Is her partner willing to leave the property?
To your knowledge has there been any violence?
You can work out what state benefits your duaghter would be entitled to here
Her partner will have to pay child maintenance of 16% of his gross income at most.
It is unlikely that he would have to pay anything towards the mortgage in addition to the child maintenance - but your daughter shoudl be able to prevent a sale whilst the children are under 18 (and she does not cohabit)
In the absence of Domestic Violence your daughter will need to try and negotiate with her ex using Family mediation
but if he refuses to leave she can make an applictaion using Schedule 1 of the children act to ensure that she and the chidlren can remain there alone.
I hope that this is of assistance - please ask if you need further details