This is most common fear of people who don't know about psychiatrists, they are usually reluctant about there first few visits. You require to make him comfortable by counseling him that it's OK to just visit a psychiatrist once. they are friendly people and will understand your thoughts better than us. You might require a very short term treatment or maybe no treatment at all, you just have to tell about your problems and that's all. And I will be there with you there is no need to be worried about anything . you will really feel better . It works in favor if you make a bond of trust with your brother as it will be useful in case he requires treatment.