But does Sabrina have permission from Mami to share her personal details?
If it's in the name of reconciling her and her former friends/students, I'm sure she wouldn't mind. Especially since the image/impression she'd built up of being perfect and without problems was a big part of why she had so much trouble making and keeping friends. It's actually fairly ironic--she built up this image of being "the perfect sempai" because she was afraid that if people knew how lonely and in pain she was deep down, they'd abandon her...when it was that very facade that facilitated her friends/students abandoning her so easily--they all just assumed that Mami would be totally fine without them, based on how Mami acted around them all the time. It's also part of why those same people didn't keep in touch or reach back out to her--the image of a perfect magical girl they'd built in their heads was probably off-putting and intimidating, especially when compared to the serious problems they themselves were facing (like Masami's injuries, Kyouko's dearth of Witches to hunt, Kazumi's struggle to sustain a team of seven magical girls without enough Witches to farm, etc).
Like, if Mami were here, we'd quickly ask her for permission, but this whole issue is
why she isn't here.
It's also an important bonding experience with Akemi and Noriko (and, to a similar extent, Masami and Hiroko), too. Them realizing that Team Mitakihara has its own share of personal problems/trauma/fears will help humanize us and make us relatable. I think, deep down, there is a sense of shame and inadequacy that the two pairs we're with feel about themselves, because they tried to make it on their own but essentially failed and suffered heavily along the way. Revealing that, hey, even
Mami was secretly suffering a lot and was devastated when she learned that Kyubey was just using her and deceiving her all along would do a lot to make them feel victims of a deeply unfair system rather than people who failed on their own merits.