This scheme does not work for US citizens. He would have to pay a significant exit tax to give up his US citizenship.
This is the real problem. The EU shouldn't allow sale of citizenship in host countries, essentially paying a way to get into the EU. I highly doubt that would be possible to enforce though.
it is a hotly debated topic in the EU and seems to be up for removal in the current years, especially in the current political climate.
The Cyprus passport scheme has ended this month, only applications submitted before the end of October are considered. The same I believe applies to Malta which had a similar scheme.