The Autopsy Report might prove interesting re what might have caused the sudden collapse....and a review of his flight medical records and other medical providers if he had any.....along with prescriptions, and other factors.
Perhaps his family may be aware of something he had complained about but did not think serious that might have been a waring sign.
I have had two friends both age 46 that had massive heart failures and died within a minute after being stricken.
One knew he had serious Heart problems and was scheduled for a proper exam to determine treatment but had the big one just before getting into the car to head to the hospital.
The other one was driving into town to do some grocery shopping and was found slumped over in the seat of his pickup on the side of the road......he had been having some minor Heart Palpitations and had been scheduled for a visit to his Primary Care Physician.
It aint just old Geezers that get struck down.