“I think you and I just differ on the meaning of natural born citizen. I think it means citizenship at birth and you probably have a more complicated definition.”
By your definition, he is also a Natural Born Citizen of Cuba. Actually more Cuban than American as his mother had renounced her US citizenship 2 years before his birth.
His mother had been a US citizen, but was Canadian at the time as per the Canadian government records.
I leave it to the Cubans to decide who is or is not a natural born citizen of Cuba. It is none of my business what they do.