Dean doesn't remember his mom dying. He remembers the fire; the heat of it, the smoke, thick and cloying and pushing so deep into his lungs that he'd remember the taste of it until he died.
But Dean doesn't remember his mother dying. He just remembers what happened after. The crippling loneliness, the worry, the picking up and traveling at a moment's notice to hunt down creatures plucked straight out of his worst nightmares.
Sometimes he wishes John had died in the fire instead of Mary.
Dean doesn't remember his mom dying, but sometimes he wishes it had been him.