Unless he has a retirement plan, or owns his house, or has a stock portfolio, or pays money for goods and services, or has a job for which he is paid a wage commensurate with his talents and skill at negotiating, or the work of a labor union. Then he is a capitalist.

Capitalism and socialism aren’t antithetical. Saying he isn’t a capitalist is more ideologically in line with what Marx called scientific socialism, or “communism”. Communism and socialism are not the same thing. Equating them is one of the reasons right wing lunatics can effectively take shots at socialists: so many Americans who call themselves socialists are really espousing communism. Those people are either being deliberately deceitful, or they are just idiotic.