It sounds like it's a valid will. How long was he married to your mother versus this woman?
I was a little unhappy with my stepmother's death because my stepsister got the money from her grandparents that had been "saved" for her all these years and my 3 brothers and I got the money from our grandfather. She got like $125,000 and we got to split $8,000 by four :-) then the rest of the estate was divided by five. I was wishing the whole grandparent thing was proportional to the whole and took into account the passage of the years, etc. I guess that is asking a bit much. The executrix was my stepsister's daughter and her husband was a partner in a large firm that did the whole thing, very expensively, not entirely their fault. My MBA brother had been doing our stepmother's taxes and hadn't done them for seven years prior! So, the law firm first had to hire an accountant to try to get the IRS to work on that. All the inheritance was in stocks, they didn't sell them or do anything with them, so in the year it took to work on the will with all the complications, the stock market took a dive so we lost probably $400,000 out of the estate, etc. There had been a lien on the will from my parents lending money to my n'er-do-well brother-in-law, it was to come out of my stepsister's share if she had died before he did but he died first so my brother's and I excused that debt. My brothers and I are all well enough off and grown so they didn't really care; my brother who messed up the taxes (lives in Hawaii) didn't even claim his portion, was screwing up the whole tieing up sequence really bad. He has gotten strange the last 10-15 years, doesn't want anything to do with the rest of us. I have no clue about my niece anymore, she could be married with kids and I wouldn't know.
It's sad how families pretend while everyone is living that it's all fine and dandy. I didn't realize until after my father died in 1992 how I'd bought into a myth about my whole family. That was a lot of what my T and I worked on 1996-2005. It took my father's death and the disintegration of everything I'd built into my fantasy of "family" (changed again but more toward the "better" when my stepmother died in 2001) to really get me woken up and smelling the roses :-)
I'm keeping up with you because I have that redheaded stepchild, remember