You are right I don't know for certain that there wasn't a “deathbed” conversion.
The scriptures say that it is appointed for man to die once, and then the judgment. None of this good works business.
‘After death’? Seems to me; that is the most likely ‘time’ per Judgement.. .but then; what do we know about the timing of a soul’s judgment. I would offer - we know nothing about God’s timing. And given God is all-wise; suspect He can figure the ‘when/how/what’ per his own disposition.