This thread or one like it is going around. Shotgun vs. AR for an inexperienced or totally novice shooter.
Both are bad choices. Get a SW Model 10 and load it with one of the lesser recoiling HP self-defense loads. Or a similar Ruger revolver.
Then the newbie should take a basic handgun course.
I've seen guys complain because their elderly arthritic wife wouldn't take to a pistol grip only 12 gauge. Lots of stopping power and won't miss - by GUM!
Give me a break. That's what I would tell someone. However, I learned my lesson at Cabela's listening to such a conversation where the newbie wanted a pump so he could just rack it to scare the bad guy and wanted some blanks if that didn't work.