Wow, that was quite... all over the place. O_o
Aanyway, I hope that this is the last chapter with sexual assaults and that we'll actually (dare I say it) see some legitimate development of Yuzu and Mei's relationship!!? The conclusion comes after Yuzu realizing the Mei just needs a supportive family. I am speculating that Mei's father has issues with her following her grandfather's (possibly her dad's dad) orders. (Such as the one with her being engaged to that teacher maybe.) Thus, she was mostly following orders and being told what to do, thus she either lashes out randomly (as in kissing Yuzu early on) or acts like a hardcore sub. But I think she isn't being a hardcore sub anymore after meeting Yuzu and seeing how Yuzu's personality is, especially when she clashed with her rather strict grandfather.
In regards to Mei's collapse at the end, I think it's a mixture of overworking herself and the intense emotions that probably ran through her at the cemetery. It's clear Mei showed some maturity in realizing that she cannot run from her dad forever because she may have regrets after discovering that Yuzu never really had a chance to get to know her's.
Which leads to her dad and Yuzu's mom. Will we see Mei talk to the mom more often because there is an apparently obvious reason why Mei is with them? Or not, even though Yuzu's mom is very happy despite Mei's dad conveniently jetting off to the other side of the world.