Teenage brain works very different from an adult matured brain. It is still not sustaining enough to manage better decisions and look at consequences. I would request you to take a psychologist help first for parents and understand the communication gap between the parents and the teen. Then ask them for different strategies to manage his anger and parents reaction to these anger. Also he needs to know better study techniques, refocusing techniques. But this is not just your brothers problem parents need help too.
Next Steps
See a psychologist online/offline. With growing age parents need to grow with their techniques to manage the teen. You can't expect old tricks to work life long. Continuously upgrading is the only solution.
Health Tips
Falling in love or attraction in this age is natural and is not a issue. Also anger which is not clinical need not be addressed. His distraction from studies and refocusing on career must be your first priority everything will fall in place after that.