He already had money in there. Topped it off at $10,000 last year I should say. He can only put $6,000 per year, as you said. Anyway, got it up to $16,000 recently.
In order to determine whether he did better than the S&P we would have to know the beginning balance, the dates and amounts of all contributions, and the ending balance.
If you don't know that those are requirements for determining the performance relative to a benchmark it is not obvious that you are knowledgable enough about finance to be directing his IRA. I am not accusing you of any wrongdoing, just noting a knowledge gap.
Of course the one way to be certain to do as well as the S&P is to invest in a low fee S&P index fund. Two of them come to mind, both Exchange Traded Funds (ETFs). SPY and VOO. Either is a fine choice and the differences are miniscule. The choice really boils down to which has lower commissions at your brokerage house. This path requires no study, very little work and will get you better results than 90% of investors.