You may be able to get a loan to help with your mortgage payments while you are in prison. But, this depends on what benefits you were claiming before you went in and on how long you'll be in prison for. Someone who was living with you may be able to claim help to pay the mortgage if you cannot.
The Disability Discrimination Order can protect you from being treated unfairly because of a disability. This can protect you if you’ve been refused assistance or asked to leave your accommodation because of action that’s attributable to a mental health problem.