He and his siblings had tuition for all their core subjects and they were specially selected teachers either from NUS or MOE. And they were no ordinary teachers. They were usually the best teachers who set the curriculums. One was a relative - Philip from ACS.
The kid that asked the question probably did not know his background.
Likely Earnest Lau from ACS. Not Philip. Earnest married sis of KGC and tutored LWL on GP and history. Principal of ACS for a long time.