This is your grandmother? And she lives with you and your family? And this isn't her house? Because the truth is, no adult can be forced to care for another adult. I'm not saying social service might not make it difficult, but if your family can no longer do the caring, then social service must find another placement for her, which almost certainly means a care home. What you need to do is tell any social worker that there has been a complete carer breakdown and the situation is no longer tenable. Point out that you (as in your family) can no longer care for her and that social services must find an appropriate placement for her otherwise your only option would be to have her admitted to hospital. This is a pretty radical step, and most people simply wouldn't drop their elderly relative at A & E, but you can rather understand why sometimes they do.