Hello, I am an IB diploma graduate (um... many years ago though). In general, most colleges/universities have equivalent score conversions for IB that correspond to AP. For instance, score 5 = credit in X class, etc. In general we took tests the last two years of school. So I took calculus BC (second year of calc) my last year of school and received credit for calculus in college. Some are easy to convert, others not so much. I also, like PP mentioned, took all the corresponding AP tests. Mostly because at that time we wanted flexibility (in case a college didn't recognize IB but now I think that's uncommon).
In some cases an IB diploma = X credit hours at college but then they distribute the credits in variable ways.
A lot of IB schools start most students at a certain level and allow the students to choose a more difficult or less difficult math course to follow (similar to sciences).
I must say I loved and am proud of my IB education, but it was no joke
Expect your son to work hard over the next 4 years.
The math HL course I'm not sure of specifically (maybe it's a newer course compared to when I was in school?). If so it may take some time for the equivalent classes to be published at a college's website.
