Goku this is not me trying to push my opinion here , involuntary toxication without intent can literally absolve you from terror and murder charges.That point was repeatedly brought up that the dad being drunk isn't a defense and would show he is unfit to be around the mc especially if her tried to molest someone else. The dev didn't want to believe that being drunk isn't a good defense for crimes especially if someone is hurt in the US. Now you may find a few outliers where the judge acts like a dumb ass and give them a light punishment but they tend to be few. The biggest threat is finding a judge who he can't buy.
Criminal law of Ny state and my own country ( india ) states it in their respective sections.
Again if we were to still go book by book mia would always get the custody regardless of the cheating/ adultery allegations and you have to remember that this was not a jury trial but a single judge trial , a jury trial most likely would've stood up with mia.
Lastly , have some sense of disbelief like i sad earlier because then i can end the game with "mia won the case anyway and everyone lived happily ever after"
I mean i can add that alternate ending if you want but I'm quite sure you're here for the overall story not the legal aspect of it.