Renounce U.S. citizenship, stay out of the country. They’ll just bleed him for more and more until he does.
They won’t let you renounce until you pay your “back taxes”.
The issue in the article is no joke. I know individuals now in their 60s born in the USA who came to Canada as small children, married, had children, and are now grandparents and have lived virtually all their life in Canada.
They could be arrested for tax evasion if they tried to visit family by crossing the border. (The Canadian passport lists place of birth.) Technically, this could apply to their children also.