I think this essentially explains why taxing billionaires is not very useful, because the total amount of their life generated wealth assets amounts to a small amount for 25 million people let alone larger populations.
Even if you took all the $’s away, the government really needs to tax high numbers of lower income people for the income to be meaningful.
Getting $250 once doesn't seem like it will have a huge benefit to someone's life.
Note too that higher education in the US is partially supported by things other than tuition and so 250 can go farther than it seems because it is 250 applied to your portion of the whole... We can debate how much different payers should pay, but that is a different question.
I feel he would have been better off going to someone like Coursera and funding minimum accredited US associates degrees and delivered electronically and delivered for free to anyone in the United States.
It seems like the buying power of $6 billion to deliver electronic services on the cheap would make more sense than giving millions of children a one time amount of essentially pocket change in relation to total spending.