Are you dumb? If his atar was based only on internals he would get a 72ish atar based on school rank, CSSA being easy this year and the fact he has indicated he started bad
Like seriously:
His Maths will end up with a 75
His English will end up like 65
His Physics will end up like 68
His Economics will end up like 85
His modern history will end up like 75
That is a 70-75 atar