Coinbase was part of the YC Summer '12 batch. What are the odds he's referring to Brian Armstrong? It may be a long shot, but that would at least explain why the concern from his friend is noteworthy.
[1] - https://news.ycombinator.com/item?id=31012462
[2] - https://www.justice.gov/usao-sdny/pr/three-charged-first-eve...