Regardless, few seem to understand that we are human. We don't toss out our ability to think because some "rule" says that "unless A happens, don't do B".
And, IIRC, there's a "rule" in the FAR that says (effectively) that any of the rules can be suspended if there's an emergency. So, does someone actually have to SPEAK the magic words or not? I don't remember any FAR that says so.
"Custom and practice" are poor substitues for doing your job to the fullest extent you can. They are, as I said before, excuses. Granted, they are reliable excuses that society supports because it's easier on the lamebrains. But, they are still excuses.
And, nowhere did I even hint that ATC should have somehow flown the plane for the pilot. What I said, baldly and plainly, was that ATC needed to act so that the pilot could fly the plane and assess his indicated problem without worrying about outside issues.
And, there are a couple of factual things that happened that are being ignored. The pilot said he needed to descend. Not "wanted to;" NEEDED to. He also said there was an indication of a problem. So, add those together and what do you get? What solution, if any, would you propose? What did ATC do?
It's not second guessing. When there's a situation that develops in an aircraft and it gets ignored by ATC, then a procedure needs to be developed to avoid that kind of situation in the future.
Or, you can just blame the pilot.