1. You should have taken legal advise before selling your land without receiving money and permitting him to construct the school on your land,
2. Have you executed and registered the Joint Venture Agreement? what are the terms you have mentioned therein?
3. If there is no agreement executed by you, you should immediately write him withdrawing your consent for his building the school on your land without your receiving the said amount of Rs.25 lakhs,
4. Come to India for a few days and lodge a police complaint against him for cheating you. Have you mentioned in the sale deed that you have already received Rs.25 lakhs cash as consideration?
5. File a recovery suit against him,
6. Execute and register a POA in favour of anybody in India to del with your cases in your absence,
7. If police does not take any action, file a Writ Petition before the High Court against police inaction seeking remedy.