Minor’s summer stipend contribution to an IRA

Hello! My kid received a stipend in 2023 over the summer for $350 (no W-2 or anything) from a school program. He also received a 1099-DIV from Fidelity for a few dollars (they didn’t report it as it’s marked de minimus). He’s still reporting it.

Going through the TurboTax program for him, he owes no taxes as expected. TurboTax shows a screen that states “You can still contribute up to $350 to an IRA, but…. you won’t get a tax break this year.”

Can he still “contribute” that to an IRA as a prior year contribution? I’m assuming he has to do a Traditional IRA rather than a Roth IRA?