Actually, MIL would disagree. Paying the IRS over 50K (on widow's pension and SS) b/c your spouse, it turns out, didn't file taxes for 6 years, didn't leave life insurance, and had NO savings whatsoever, kinda sucks... There are worse things than fighting over money.
I'm getting sad continuing to read....OP, I'm so sorry you lost both parents so fast. My mom died of a hemorrhage as well...it is so fast and shocking and unexpected (though my mom was on blood thinners, her doctors had ignored the signs and symptoms of a bleeding ulcer, so it was still unexpected) and it's just bewildering.
I'm also sorry that your mom kept the information of her new will from her; that's also bewildering, when she had shared the old information with you, and had recently shared the info of what would happen if both of them died together. It's being blindsided. It's NOT fair. If you had known NOTHING it would be different, but she had specifically shared info with you about her will before, and hadn't told you that things had changed. I'm so sorry.
My husband has continued questions and anger and unresolved everything, along with the sadness after his dad died in '06. That's not a good way to grieve. At least with me, it's just pure grief for my mom. There are no complicated feelings; I feel so bad for my husband to have the complicated grief, and I feel bad for you as well.
I hope that your stepmom is a decent person and that she makes her will to reflect that some of the money she now has was made by your mom (and your...niece's grandmother, if I have the relationships correct). I hope she remains in your lives even without talking about money. It's so sad when a stepparent disappears (like my first stepdad did).

