What I hear from my Indian friends is that this guy is a checker all right, but was just flying jumpseat as a pax. He apparently is not a regular with Jet, but a DGCA (Indian CAA) kingpin who is attached to Jet to overlook their flight safety standards. That explains why Jet did not deroster him on the spot, since these types seems to be above the law.
In India with its runaway expansion in aviation in recent years there has not been time to indulge in such details as the ability to handle big aircraft in raw data. A not uncommon career path is quickly through a pilot factory in the US and then - without any further increase in qualifications apart from a quick type rating- on to a 737 or 320. That is why the government has decided that all expat pilots must leave India in 6 month to make room for thousands of highly skilled (250hrs) local heroes. And that is why it is an established fact (by the Indian press) that flying without all support systems constitutes a near emergency.
Incredible? - no, itīs India.