如果是虛擬語氣的話,if he was就不對。 就象說,我要是你的話... -->If I were you, 不能說If I was you...
如果不是虛擬語氣,if he was就是對的,想不出一個好例子,感覺虛擬語氣的時候多,除非if是當whether講的時候,I wondered if he was upset.就不能用were