Airline pilot dies after takeoff

The idea of a first-class medical is that it prevents the kind of
event that makes a pilot too ill to fly the plane.

The reasoning and criteria for medical certification can be found on the FAA
website at no cost to you, either real or simulated. In addition, the
equivalent for the European Union is sure to be available in like manner.

Go, read up, become a simulated medical examiner, and report back.