re: Child psychologist/psychiatrist in BR

If the situation is as dire as you present there is virtually nothing this family can do therapeutically. The only option is to placate this child as best possible until he removes himself from the home. Limit anything and everything that would incentivize the child to stay beyond age 18. Encourage the child to enlist in the military.
Having said that be very careful not to create an incriminating medical record that would preclude military enlistment.

This coming from someone with personal experience in the way of a sibling and an offspring. Likewise from a person with professional qualifications.

You might want to attempt Christian counseling utilizing the temperament model. Understanding a person's temperament is critical to raising that person as a child.