IMO, fluent Spanish can be useful for lots of reasons. I have a large number of Hispanic clients who would be thrilled if we could talk in Spanish - instead I am often talking to their kids who translate for them. While IB may be a smidgen more well-regarded than doing a full set of APs, at many colleges it’s easier to get credit for the APs. I also think for science focussed kids there are more AP choices. Which program has better teachers? Where are his friends going? What does your kid want to do? Those are all more important IMO that some hypothetical about college acceptance.