Thank you!
I considered that option first but I've read somewhere that you cannot upgrade part of a booking. If you want to upgrade a booking you have to upgrade all the passengers in the booking and I did'nt want to use 200K++ of my dad's account.

I've never tried to upgrade with EK so I wanted to know from your personal experience, is it easy to find 3 "upgradable" seats available? We did it last year with Air France for a CDG-NYC trip in the middle of the summer and I was surprised that it was so easy.. I don't know with EK ?