I'd say my bigger concern with Graha isn't that he lived or could use that magic far away from the tower but that the writers just skipped over the transference like was Graha our Graha a willing participant or did we just shove the Exarch into him cause that's only been shown to be the Exarch in that body now & no sign of our Graha. I for one thought he'd just get Exarchs memories but he seems to just be The Exarch they just gloss over that whole process as if it doesn't matter, I for one think Exarch should've died on top tower & our Graha should just had or been able to cycle through the memories stored on the crystal.

Honestly whole end felt like he was way way to willing to give up the Crystarium & Lyna to go adventuring with the WoL as if he had no attachment to first after a 100 bleeding years there, fact we literally have tell him to have moment with basically his daughter was a weird scene during all that.