I completely empathize with your brother. I understand his pain because I too had to undergo the same treatment by my seniors. I was ragged -- beaten up and stripped -- and even today I can't forget all the torture that I went through. It left a huge mark on my psyche. Till about a couple of years ago I used to feel completely impotent and powerless. It was almost as I got raped. I wanted revenge. I would constantly have scenarios in my head when I would kick myself for not having fought back. I had just given in to the torture because it was easire for me at that time. I revisited those scenes many times, and every single time I went through the torture that I had gone through the first time.
As a result, without realizing it I had lost trust in people and I wasn't able to make friends or even rely on my own family members. Talking helps enormously and becasue unknowingly I had become suspicious of people I never talked about the guilt I felt about this incident. Thus I was in a corner -- mentally a broken man I had become suspicious of the very tools I needed to repair myself.
I was having huge anxiety attacks.
But luckily someone suggested I got to a therapist and that helped enormously. Today i am 90 percent healed. And that too without any medication. Whatever you do find a counserol/ a psychiatrist/a psychotherapist -- that is someone your brother can talk to. Do not try it yourself. They are professionals and they know how to build a person's trust and self esteem. For all you know even you brother might be able to suceed in life without any medications.
best of luck and take care