Clearly, Tax Evasion will charge against him especially if he is residing on US. After Bitcoin regulated on certain country, Residents should pay their tax annually. Satoshi Bitcoin is sitting on his wallet for a long time and surely every government watch his wallet carefully. His/her Bitcoin might be seized in case his ID verified.  It’s absurd that he is not watching Bitcoin and knows how much money sitting on his wallet right now.

But this event is not enough to take down Bitcoin because it’s decentralized and controlled by the Bitcoin community. His holdings is surely huge but Bitcoin is PoW and not PoS which means his holdings doesn’t matter at all on blockchain functionality. Probably it will only reflect on the price.