Can Property Purchase for Your NRI Son: Even though you are not an Indian citizen but have an OCI card, you can become a tax resident in India if you have lived there for the required number of days. Also, depending on your plans, you might be considered a resident for the purposes of the Foreign Exchange Management Act (FEMA).
You would have been able to buy a house in India in the name of your son if he had been a resident in the same way. This would have been conceivable even if someone had given you special power of attorney so that the property could be purchased in your son’s name. Because the source of payment is likewise obvious, this transaction would not be considered a benami transaction under state rules that protect such transactions.
However, because your son doesn’t live in the country, this deal would not be legal under Fema since you are paying to buy property in his name.
You could also give your son the money and let him buy it in his own name, or you could buy the property in India first in your own name and then give it to your son. Both of these deals are legal under Fema.