If I have read this thread correctly - but I accept that I could have misread the details - it is reported that the controller instructed the pilots to remain at FL250. It seems not to have occurred to that controller that the pilots might not able to think clearly due to hyopoxia.
Surely the controller should have given a very firm instruction to descend? I have to wonder whether the controller could now conceivably face manslaughter charges?
Are air traffic controllers given any training about the effects of high altitude flying? As a young Air Force pilot in the 1960s, I had experience in a decompression chamber. That experience served me well when I some years later I had oxygen failure in a glider in mountain wave at 20,000 feet. Again I stand corrected, but I don't think today's civilian pilots who have had no previous military experience have even been near a decompression chamber