Im right with you. At -50/-80, he would at least have significant frostbite to fingers,toes,ears,nose and eyelids.
That low of a air pressure would cause lung damage.
Lack of oxygen for 5 1/2 hours = Brain Damage.
Id be interested if there was a access panel to the hold in the wheel well.
I think he hopped in the cargo hold.
At 25.000 feet you will collapse and death is imminent unless oxygen is restored.
I suspect cases where people have survived extended trips in wheel wells were below the altitude claimed in this story.