That still does not follow. It proves that he lied about not knowing what bitcoin is and it proves that he had bitcoins. Those two facts do not prove that he is Satoshi. It is not obvious.
Here, I'll give you an alternative explanation:
Dorian was an early bitcoin adopter or otherwise had a small number. When reporters started asking his son if he was Satoshi, he realized that that would damage his reclusive lifestyle if people thought he were Satoshi. He thought that telling the truth, that he knew about bitcoin but wasn't Satoshi, wouldn't be believed so he told a lie to preserve his reclusive lifestyle.
Well, you're just taking that it is not logically imperative that he be Satoshi as a counter argument. I think if all is true that it is a pretty interesting coincidence given that, despite people think here, Bitcoin was not a very common thing for normal people in 2011.
But anyway, this eye witness seems a bit odd for other reasons.
Here, I'll give you an alternative explanation: Dorian was an early bitcoin adopter or otherwise had a small number. When reporters started asking his son if he was Satoshi, he realized that that would damage his reclusive lifestyle if people thought he were Satoshi. He thought that telling the truth, that he knew about bitcoin but wasn't Satoshi, wouldn't be believed so he told a lie to preserve his reclusive lifestyle.