He should really, really take the SAT and ACT this June. December is too late for most merit scholarships (their deadlines are between October 15 and December 1st, and he should plan to take the test at least twice before that, although some students need 3 attempts to reach a merit-worthy score).
What are his predicted IB scores? They may matter more than his GPA.
Is the 3.2 a US school GPA or your estimation? Because you said he was a very good student and in the US 3.2 is not “very good”, it’s more like a 26-28 on the IB.
He needs to take a full SAT and a full ACT practice test and see which one he does better on - it depends on students. Many European students do better on the ACT because it’s a bit closer to the type of questions they’ve encountered before.