Maruti Suzuki India — about nre scheme for blood relation (rs.5000) while purchasing new car

Address:

Perkattu Moolavilayil.Manjadi p.o Tiruvalla 5, Pathanamthitta, Kerala, 689105

Yesterday i purchased car from our tiruvalla avg showroom. As per new scheme nre blood relation offer is rs.5000. My elder son is working in us and he is a green card holder (Permanent residency). But as per suzuki they want oci card. Oci card is for us citizen holding us passport. Please see the us visa site. But suzuki refused this offer. Please clarify while not given nre offer of rs.5000. He is working in us since last 7 years. (Same address of purchaser of car). If not paying nre offer then what is the category.
My younger son is working in dubai with same address with visa and emirates id. But that also rejected
Then what is this nre scheme. Please clarify