Another query about getting name of mortgage

[stepper]

My son got divorced two two years ago. As part of the divorce settlement he agreed to transfer the house into his ex wife's name. He has remained on the mortgage since but has not paid anything. His wife has been cohabiting for two years.

The building society have now come back with the suggestion that he can transfer the house into his ex. wife's name but he remains liable for any debts that might ensue. He has been asked to sign an agreement to this.

If he does so, it would mean that his wife owned the house outright and could borrow more money without referring to my son. He would be liable to any of this new debt as well as the old.

He is going to suggest that she remortages the house herself, sells the house and keeps any equity (there should be a small amount) or remortgages with her new partner.

Is there anything else he can do.