There’s an excellent case to be made that Benedict didn’t fully resign, but was more like an old sheriff that said “I need a deputy to help with this job”.
He is, in many respects, acting like he still thinks he’s pope.
I have no idea what the old sheriff quote you cited means. If you think there is an excellent case to be made, by all means make it.
As far as Benedict acting like he still thinks he’s Pope, have you ever seen a Dad at a family business giving it to his son, but still thinking he’s boss? I’ve seen it all the time, and have even seen my father-in-law and brother-in-law live it. Doesn’t mean he was still the boss, but he certainly acted like it.