Are you travelling QF103? Or 93?
QF103 looks to have around 14 spare Business seats. In Economy, it is about half full, but the "status" rows are completely full.
This means that you have a reasonable chance of an upgrade, but depends how many business seats they release for upgrades and how many other Plats are in Economy.
QF93 looks to only have a few seats left in Business. Probably a bit less of a chance than QF103.
Good luck! Being a plat your father has put you pretty much at the top of the list. The only thing that matters is how many business seats are released for upgrades and how many other plats/Chairmans lounge members are on the list before you...
If you don't know how the upgrade system works, basically upgrades are done in the order Platinum to Bronze. For each status level, upgrades are done according to the time of request. So a plat requesting an upgrade 3 days before the trip is higher than a gold requesting 2 months before a trip. A plat asking 2 months before the trip is higher than a plat asking 1 month before the trip etc etc etc.