Duck Pilot
Perfectly safe with the proper training. But the event scenario you draw not a common occurrence hopefully!
But if it happens, full use of automatics, and ATC help, and probably not divert to an unfamiliar airport.
Low houred ex cadets are a common occurrence in UK airlines, F/Os with that experience operating two crew ops in Europe with BA, Easyjet etc. A320 type.
There is no large pool of ex GA or Military to draw on, so airline financed programmes required and in place.
Trained at Flying College after rigid selection and thorough training, to CPL/IR, (ATP exams completed) and then further airline line route training and mentoring after Type Rating course.
Incapacitation scenarios that you depict are practised regularly in the sim as you would expect.
Much better than 1500 hours instructing in a Cessna 150??