the family cannot have somebody sectioned. Under the mental health act it takes two doctors, a social worker and a member of the family to have someone sectioned, and its only if they are a danger to themselves or others, or have totally lost reality, and then its only for a short while.
He needs to see his GP asap who can arrange an assessment with his local borough's Central Mental Health Team, who can then decide on treatment, which can be drugs, or therapy, or both. These symptoms can also be caused by epilepsy. Get him to a GP, before it goes further.