Well I assume if they had a joint mortgage then they had a property which they still jointly own? Your husband would still be liable for mortgage payments if she defaulted as they both are responsible for the mortgage. Does he pay any maintenance to her. I would get another solicitor if I were you, he either needs to buy her out and get his name off the title and the mortgage, or they need to come to some arrangement. He could go along and possibly change the property to tenants in common instead of joint tenants (somebody might put me right on this if it is not possible) and then they would have to notify her if she objected and that might 'smoke her out'. It is a can of worms that is all going to open at some stage in the future and it could be very costly for you both if you don't get it sorted out legally. So I would go to a solicitor who specialises in such matters.