PS3 code and "Playstation network" / "Square Enix" account understanding.

[KatoKinko]

I'm sorry for posting this Thread. I'm not even sure this is the right place for this.
But when I was reading Reinheart's Translation (JP to English) thread. A interview with 4Gamer mentioned something about the PS3 code on your PSN account.

My borther wants to play FFXIV:ARR for the PS3 when it's released, and I want to buy a PS3 copy so I can play on the PS3 too. But I don't know if he will need to have his own PSN account? We share the same PSN account and buy w/e games we want so we can both play them.

I didn't know if all you needed to do is have the PS3 code in you SE account to be able to play on a PS3, or if you will need to link it up with a "one" PSN account. Meaning he will need to make his own account to play on the PS3.

I'm sorry for the long post but can someone help me understand please? Thank you.

[Edit]
I dont mean we have our own PS3's, we live in the same home and share one. I ment I could be playing on the PC and he plays on the PS3, or maybe I play on the PS3 and he plays on the PC. That kind of thing. I don't mean to play on two PS3's.