thank you for your help, I hope someone comes forward with some advice on which way to turn first

my daughter and her ex partner have a joint mortgage plus a secured loan totalling £90k. He has just been released from prison for theft. He has told her it will be in his best interest to declare himself bankrupt, leaving her with the debt. He is being fined for proceeds of crime. There is no way she can take on this on her own, she has 2 young children who are his. She has been paying the mortgage herself but interest only for the past 2 years while he 'sorted himself out' She knew nothing about the theft, it turned out he was living a double life with another family. The house is already in negative equity, probably worthless, due to next door being converted to probation flats full of rowdy young men. I cant help her financially. All complicated and none of her doing. Please can anyone suggest where we turn first. If this is in the wrong section please advise, this is my first time on here. Thank you