Predict this divorce settlement? Finances, assets, etc?

I am a 19 year old college student living in a very tough situation. I have known that my dad was emotionally abusive to me, my mother and my younger brother for as long as I remember. I don't want to give away too much info, so let's just say that he's gone to therapy funded by his workplace. He also completely berates me and my mom and makes us feel like his dogs. He's threatened to cut me and my mom off numerous times. He always claims that we are torturing him because we don't meet his every demand. That's how bad it is.
I'm probably an idiot for posting this on y.answers but I really need help.

Here's their situation:

-Married for 21 years
-Parents have a joint bank acct.
-Mortgage will be paid off on the house in two years or so. House is worth $500k
-Dad used to make ~$50k but got bumped up to about $180 - $200 k 10 years ago. Now, he makes $380k including bonus
-Mom went back to school in order to feel more accomplished. Her self confidence was really low due to my dad's emotional abuse. She now works part-time and makes $50k.
Her self confidence is still very low, at least in my opinion.
-Only debt is the mortgage and two cars. The loan left on the two cars is less than $20k.
-My dad has a huge 401k (I think above $900k) but my mom's is pretty measly in comparison.
-My dad also has a lot of money going around for investments. Not sure how much though.
-younger brother is 16 yrs old (still a dependent)
Added (1). If I were to estimate my dad's total net worth, I'd say that it's definitely coming close to the $2 mill. Range.

Given this info, what will the divorce settlement be like?

I know my mom is just staying with him to provide a stable family life for my younger brother. My younger brother has autism & he will have a harder time adjusting to changes compared to most 16 year olds.
However, my mom is really thinking about leaving him soon. The emotional abuse is getting too big for her to ignore.
Added (2). and yes, there is significant evidence showing the emotional abuse that he puts me & my mom through as well as his colleagues.
Added (3). He asked if I park my car in the assigned garage at college and I replied with, "I don't know" three times. I was under the assumption that he was asking me if I am going to park there next school year, as in fall 2016. I didn't know that he was asking me if I parked in the assigned garage CURRENTLY.

It was this instance that caused him to stop paying for my tuition because I'm "disrespectful"
Added (4). All the money my mom makes goes to me because my dad refuses to support me because I'm disrespectful. He only likes my younger brother because- I sincerely don't mean this in a rude way- he's autistic and simply listens to everything my dad says. He sits at home, studies, and acts like an 8 year old child with very limited free will. He has a car and a license but never leaves home for anything but school. That is why my dad likes him. My dad likes to control people.
Added (5). My brother is also on medication that controls his anger issues. Under the medication, he's very sedate and easy to control. It turns out that my brother is the ONLY person that my dad never has issues with.

I should also note that he's been married before and NEVER talks to his ex wife and two daughters.

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