I can't imagine how hard things are for you right now. If anyone can do this gracefully, it's you. Please try to take care of yourself and allow little indulgences when you can afford it.
I'd definitely talk to a good divorce attorney about your father's accounts. You need to document that you were serving in a title holding capacity only. Not sure about your state, but we have fraudulent conveyance laws that prevent people from successfully transferring assets out of their names once they are aware of creditor claims. For example, if a neurosurgeon transfers all his assets into his wife and children's names right before a malpractice suit is filed, the assets would probably be put back in his estate.
I know that for estate tax purposes, title holding in order to avoid probate is not considered "real" ownership and the title holder has to show that she made a contribution to the purchase price of an asset to claim it as her property.
Things differ from state to state, and I was told at least here in HI, divorce law is created largely from the litigated cases, and not through hearings at the legislature. One good program we have here is called Kids First and it's a court mandated program for divorcing couples with children. They all (parents and children) have to attend sessions, some together and others segregated between parents and children. They have some videos and psychologists and social workers who work with the family members in order to hopefully minimize the problems for the children.
Hang in there and be tough for your children and for you. At this point, I think you should focus on getting whatever financial gains you can. Your husband is breaking up the family and he should pay for his selfishness. This is not meant to say that your settlement should be punitive to him for the sake of being mean. It's because you sacrificed so much for him and your family during your marriage. You need to have resources to be able to raise your children and have a decent life after he's gone.
Good luck! You can do this!