@cucci Thank you for your reply! 🙂 From what you said, his visa validity is until "Must Not Enter After Nov 2018" (specific date is Nov 21, 2018)? So does it mean that if he enters November 15, he can only stay until November 21, and NOT February 15, 2019 (following the 3 months stayed allowed after each arrival)? This is where I get confused because I read a lot of conflicting info everywhere 🙁
How I understood it originally is that the Must Not Enter After date is the last day you can enter Australia, but since the visa has the 3 months stay period clause, it's possible to stay beyond the Must Not Enter After date and your visa is still considered valid, yun nga lang you can't enter Australia again once you exit, unless you apply for another visa.
I guess we can confirm this once he gets back here since visa validity will be reflected on his VEVO record. When he entered Sydney last July 7, on his Vevo, it says there his visa is valid only until Oct 7 (not Nov 21) because of the 3months stay clause, that's why I thought his visa will be valid until December if he enters again this September.