Yup, I was also
at the Choso one after the Kenny as Yuji's mom revelation. But the point of the fake memories is that Yuji makes the other person live through something that didn't happen. Regardless is Choso is his brother, the memory he saw never really took place...
Maybe the trigger for Yuji is having some sort of connection to the other person when he's about to die? Todo's was after Yuji told him he liked the same type of women and Choso when he mentioned his bros right before the final blow
If we never get a real explanation about what the fukk the fake memories are about I'ma be pissed. To me, that's the most compelling question still unanswered.
Tbh, Gege does exposition flashbacks real quick. Like half a manga chapter and at most 3/4, so I don't think we'll ever get any sort of deep dive into anyone's past and at most we'll get some panels explaining some basic question that are still unanswered about those three.
At the pace he's writing, it's 33-37 chapters a year. I'd be surprised if he's able to wrap shyt up in less than 25 chapters from now but then again he was able to wrap Culling Games and move to Gojo vs Sukuna in the span of 1 chapter and a half when there were still a whole bunch of questions and unresolved shyt about the CGs. So there's always the possibility of Gege saying fukk it and ending shyt in very quick fashion and leaving everyone pissed off and having to head cannon the entire ending