Yes, he should receive the third stimulus. If you made a mistake in reporting the amount of stimulus received, the IRS will identify the error and adjust your refund.
Please read the answer to question E1 of this IRS Q & A and this TurboTax Help topic.
For information on when you can expect your stimulus payment, check the IRS Get My Payment tool which will be updated starting the week of March 15th.
-for additional information follow this link-
2020 Stimulus: Tax Relief for This Year's Taxes