i'm so lost

I think Lysbet is keeping up appearances to seem like she's looking out for Sylhan's best interests, it also seems to me like she carries guilt for something she and her brother and their relative the Khallak chancellor or whoever she is may have committed against Sylhan that led to his father's death and Sylhan's memory loss/madness and where he thinks he killed his own father (I suspect he actually didn't or there may be some sort of twist where it wasn't his fault at all). They probably wanted to usurp Sylhan's position, Lister's behaviour of always wanting Sylhan's obedience hints at this like he couldn't wait to get a higher status than Sylhan so he could order him around as a higher ranking noble.

yeah i thought so too, it's all a conspiracy to usurp MC's position and they're all in on it.
but it seemed like the the ''medication'' sylhan was talking was actually causing his memory issues/seizures and that's why ML and the new doctor changed it. so i thought Lysbet would've wanted to keep him medicated, but in this chapter she seems to want him to actually regain his memories?? is she trying to reverse the damage cause she feels guilty? or is she lying and is actually happy with the new doctor saying that with the new medication MC's memories could take longer to return?
they're all so sketchy idk anymore!!

She's trying to keep up appearances that she's trying to help MC! But she doesn't actually want him to get better, which is why she was fine with the old medication that suppressed everything. The new medication supposedly suppresses the memories but helps the mania, which would be more beneficial to Lysbet, but if she quickly agreed, others could get suspicious of her actions. This is why she asks for MC's opinion, to "place" the decision on MC so she doesn't have to take responsibility directly. While she may feel guilty, she is 100% on her family’s side, so she is ensuring that MC doesn't regain his memories at all. But the sorcerer is helping MC and he's covering for the sorcerer to gain back his memories, and the headaches are most likely related to that.