This not a case of a pilot being sick.
It is the case of pilots collectively using 'sick to fly' as a bargaining tool for better rostering, wages etc.
DGCA asks Jet Airways to furnish details on flight disruptions - The Hindu
Flights disrupted as Jet Airways pilots fume over new roster, report sick | mumbai news | Hindustan Times
Who's right? IMO Neither the Airline , nor the Pilots.
As the way to deal with issues from both sides need more thought than blackmailing.
DGCA is stepping in to protect passenger interests.
Corrupt as they are, in this case, it seems needed.