or a solicitor. The child's father has the obligation to contribute to the support until he is 16 (or 19 in full time education), whereupon your son could make his own money and support himself. I think it wouldn't sound too unreasonable to expect you to downsize if there are only 2 of you living there. it also dosent sound unreasonable for him to have some of the equity now in order to find somewhere to live, but i'm not sure he can force a sale for this. It sounds unreasonable for him to continue paying the mortgage when he's not living there though