The length of time to stop somewhere en route to get medical assistance can vary hugely. It's not quite as simple as let the passenger off carry on to destination. There's plenty of paperwork to organise, and to set up the flight deck alone takes a good 20 mins at a frenetic pace. Who knows how long the patient was attended to prior to them disembarking, then there's all the bags to go through to find the people's bags who have disembarked. All this done at a provincial Spanish airport who would probably have had minimal ground crews to be able to attend to the operational requirements. To put it into perspective, I had a death on board just before last Christmas, we were 2 hours on the ground at a major international airport with excellent handling facilities.
Sounds like Jet2 did an excellent job in looking after the affected passengers
