Talk to Psychiatry on My Brother Is Depressed

hello, my brother has been going through issues. he started to get isolated gradually. in the past he used to get very angry and lose his temper, he would shiver and shout and cry. he does not have a job and does not look for it. he has completely isolated himself, does not go out at all, does not meet anyone, does not talk, just stays in his room mostly. he also seems to not be able to sleep properly and has back pain, also so abdominal problems. what I want to ask ke usko kis doctor ko dikhaen, psychiatrist, psychologist, neurologist, therapist etc. plz help.