Your Brother might be suffering from a psychotic illness.
He needs to take medication. How long this is going on on.
However I suggest him take medication. However he can take medications initially till controlled behaviour,
However he needs to answer a few of my questions like whether he hallucinates?
Is he depressed?
any drugs of abuse/
whether talking to self/
any precipitating factor his age/
is this first attack/
any medications given
premorbid history are all necessary to come to a final diagnosis.
later an advice can be given.
an interview with a psychiatrist
would be helpful.
or you can go online consultation, we are happy to interview him.