Thank you for your Question.
Sorry to hear about your brother. It is difficult to handle young blood especially when they aren't ready to listen.
I would suggest you ask someone else, other than your immediate family member, to speak to him (someone he would listen to)
Also, take interest in his interest. It maybe hard, but this interest will bring love and understating and then slowly he will open up and start listening.
Youth tend to find comfort in friends and doing what he is already doing. Be that comfort in his bad times. When everyone in the family is cross with him. Offer love and understanding. Tell him you understand that it’s hard but well you’re with him and are ready to listen to him.
Things that will play with his psychology will really help.
Also ask your parents to read this dua. Pls assist them in reading the meaning too.
In my prayers,