Friend's courses

My friend is really smart and is literally on the way into going into MIT or any of the IVY league colleges in the future.
As a freshman in high school, he will have all advanced classes (doing 1 pre ib course) meaning that he has the most challenging schedule possible.

My question is, with him being so ahead, how hard will it be to become a valactorian and go into a really presteguious college? He is doing the IB program, and since he is going to major in enginerring or medcine, does not know if he wants to do chemistrey honors or AP physics 1.

Chemistrey honors will go into IB Physics hl 1 while Ap physics 1 will go into IB Chemistrey hl 1. Since he mostly wants to be an engineer, should he simply do Chemistry honors? Thank you very much! I will show him the post once I get some helpful replies.

The IB program is not really ideal for STEM-oriented students.