>"If you don't graduate you don't have the brand. He might be able to establish an independent brand with his plugin, but that is certainly more risky."
>"A BS is a filter that you'll find for lots of jobs (or graduate school); and although there are places that will hire you, it makes things harder than they would have been otherwise."
I would disagree with both statements.
Part of the value (really, most of the value) of attending these schools is the network that you build while there. And yes, he can always write on his resume that he attended Yale from "Sept 2009-January 2013" (if he were to drop out). I attended a top university and dropped out my last semester to pursue tech related endeavors. I have reaped enormous benefits from this decision.
Once you are accepted to a top university, 90% of the "brand"-ing is complete. If you are resourceful (as this young man clearly is), the rest will take care of itself.
With regards to your second comment, the idea of a "BS as a filter" is losing credibility at an exponential rate. It might seem counter intuitive, but a top tech employer would take a second look at a Yale dropout who wrote a popular plug-in. A majority of applicants at these firms already come from the best schools in the country. On it's own, even an ivy-league degree isn't as great of a filter as you might think. (Note: This applies to jobs with the highest concentration of ivy-league applicants)