Cardiac catheterization recovery time
First of all the drugs were administered by medical staff during the procedure for sedation. It's a stretch to say he "used" the drugs.
The day after it is recommended to plant oneself in an armchair and do nothing.
As for driving, one clinic advises not to drive for 24 hours; another for two days.
It should also be kept in mind that this was not likely his first cardiac catheterization and that two days later he felt ready to fly.
The human factors report says nothing about how much time should be required before flying again.
Recovery time for pilots after a procedure with sedation would be a worthwhile avenue of inquiry. Would another day or 2,3,4... off have made a difference? There's no data offered here.