Question: why did his sons buy ETH? Is something going to happen today? I don't believe they bought it for no reason. They do everything to make a profit, even through market manipulation.

This tweet is from moments ago where President Trump announced a reserve of Bitcoin $BTC but also stated in his speech that the United States will not buy more Bitcoin.

Look at what happened to the market moments ago and you will understand this important financial principle: Buy the rumor and sell the news.