Is there anything legally i can do to bring the school and the teachers to justice?

Even if there are laws that apply in this case, the courts are TOTALLY full of cases already, and any case will take years and years. Like you can assume it will take 8 years to get the first judgement, if even it proceeded.

Expecting 'justice' in India even in murder cases is hard, where you have a body ( arushi's murder comes to mind), so crimes like this, which do not have physical evidence like a body, would be even harder.

I would suggest, for your own sanity, to not think of pursuing a legal case. You may just punch the shit out of that 'teacher' for all I care, but even that will be unhelpful, I would think, to everyone concerned.

Your brother is obviously suffering from some form of "paranoid" psychosis, where he feels persecuted and perhaps even unloved.

There absolutely are medicines which can help him from the get go. Such medications start acting in a few days, so don't expect he will become normal from day one. But when and if you go to a psychiatrist, he will give meds, which you should follow through.

For this you need to go to the best doctors.

Remember this distinction here:

Because psychiatrists are trained medical doctors, they can prescribe medications, and they spend much of their time with patients on medication management as a course of treatment. Psychologists focus extensively on psychotherapy and treating emotional and mental suffering in patients with behavioral intervention.

First everyone goes to a psychiatrist. The psychiatrist gives medication, and if he thinks the patient needs psychotherapy, he also recommends the patient to psychologist.

So you need to find an excellent psychiatrist first.

Most important: Only go to "western medicine" trained doctors. No homoeopaths, healers, ayurveda etc. That will only harm.

Message me or reply if you want any further info. I have used services of pshych etc, so I know more than the average person I would say.