@Compmom makes a good point that he can take Introductory Physics in college. Do you think he will?
However, yes, if the schools to which he’s applying will not care that he’s only taken two lab science disciplines - although three years of study - then he’d be fine dropping physics. Though it’s a pity he can’t drop those other classes instead! The idea of sacrificing physics for resource management or Teacher’s Aid seems rather sad.
I can’t remember - are there any rigorous academic admission schools he’s considering? Are you hoping for academic merit awards? I would agree completely with @Compmom to not worry any further about class rank or even his GPA, as long as it doesn’t plummet.