Steal PS4 account?

I Really ask for a friend

Namely, he has Zoff with a buddy of his, and has the account data of his PS4 account. He wants to steal the account now, but I want to advise him against it. Can Sony do something about it? If so, I would use that as a lever

Who owns the credentials is the owner of the account. Since even Sony can do nothing.

ps.: Why do not you advise the victim just as a precaution to change the password?

Unfortunately yes. Nobody reveals his account details, not even family members.

He can have the data. The owner has the mail address and security question!