Weird title. They never managed to get in to the phone. They just took the SIM out and put it in another phone to use 2FA SMS codes, along with logins they found written down.
No one else, not even Apple, can access end-to-end encrypted information [1]
I agree with your definition of hacking but the explicit goal was to get into their mother's phone, which they didn't. Ultimately they achieved their goal, yes, but via a different method than the one they originally attempted.