Questions regarding Square Enix and PSN account

[DreamAngel-Ren]

Yes as long as she logs into the PSN account that the game is registered doesn't matter what PS4 you use.

The thing is though, we tried that before and it didn't work. She logged into the PSN account on her bf's PS4 and tried to log into FFXIV, but the game wouldn't let her in because apparently it wasn't familiar with her bf's PS4 or IP(?). When I tried to log in (at home), the game said that due to some suspicious activity to my account, they had to block it, so I had to change the password in order to get back in.