Note that neither CS nor psychology are on it, though both are considered “helpful” for the respective courses in CS and psychology. Admission requirements for 2024 entry | University of Oxford
Note also that none of the joint philosophy schools require, recommend or even consider as helpful any specific subject for the philosophy side, merely for the joint school (ie maths, a modern language, etc) with the exception of philosophy and theology, which considers “a subject involving essay writing” helpful.
So, no point in shooting down any combination yet as long as it involves calc BC. Let’s hope that whoever your son has written to will commit to acceptable subject choices in writing. The priority is getting those three 5s.
OP, that is again the nice thing about Uk applications: while not as legalistic as German requirements, if they say that calc BC fulfills the minimum maths requirement as far as formal exam scores go, they mean it.
Beyond that, the options are more flexible. The most important “showcase” is the MAT, but again, if he’s the right kid for Oxford, preparing for that one is his kind of fun! I recall that he has done very well in some kind of math competition, forgive me for not scrolling back up, has done advanced math summer programs, is planning to do another, is running some kind of program in his high school. He can talk about all this in his “personal statement”, which is not like the common app essay in the US at all, but has to be about his chosen subjects, so yet another place to talk about both his love for and his achievements in math beyond calc.
And lastly, he can show what he can do directly, and talk about what he’s done since, in his interview, mid- senior year, 7 or 8 months beyond the AP test.
Don’t sweat the AP tests too much. I understand they’re a PITA to organise for you, but it’s just a few months from now that he’d have to focus on them. Again, if he’s right for Oxford and Oxford is right for him, they shouldn’t faze him at all.