My friend's dad was like this. One day when we were teenagers he had a pool in the backyard and we had towels on our shoulder and swimming pants on and we're walking towards the back door. His dad turned and said, you guys going swimming? We said, yeah. He said, in the backyard? We said, yeah. Said, thought so. Still not sure if he was fucking with us but he used to do this kind of shit all the time.
I think mom's hiding an unholy belief about this deep inside and is trying to discuss it with you in some way possible, but can't find an opening cause you speak the obvious so she thinks you'll be taken too aback by her unconventional approach (euphemism).
I think it's this. Mom has watched a ton of true crime mystery or something similar and was hoping her kid would reply with some grizzly details about the particulars of the case. Instead he states the obvious and mom is like "ohhh probably best not to give the kid an infatuation with erotic asphyxiation so maybe I'll drop it."
I actually got hired working for this guy, went to the orientation and everything, was hired to be his marketing manager, but he was a douche and I ended up taking an IT job I got offered right after I started training for this one, and starting my career in IT instead. He was the owner of Three Rivers Dental in Pittsburgh. He was real used car salesman-like. Wanted me to push care credit on everyone. Fuck this turd.