Can you transfer ps4 games/accounts from one playstation to another

I just bought a used ps4 for my 5 year old nephiew. It came with the previous owners psn account logged into the playstaion but not the playstion network. His passwords have been removed, and i have no access to them. I understand i can still play the games on this new used ps4. My question is, is it possible to put the account (and by extension the games on it) on a flash drive to bring them to my personal ps4. The collection includes the demo for P.T. which is quite rare i'd like to keep it for myself.

Games are non-transferable between accounts and systems, they are protected by DRM (Digital Rights Management). The owner is able to download them onto a new system, but they can't be transferred over USB or other means.

Digital games only work on the account that purchased them, and other accounts on the same system if the user who purchased the games has set the console to their "Primary" console.

You may be able to play the games on the console they're on, but you won't be able to play then on other accounts on the same system, assuming the previous owner has deactivated the console as the "Primary".