My dad's property

My father married this lady 13 months before he died. she died a year later she had moved out of my dad's house. and move to San Antonio so who gets the property her children who are not my dad's or us my dad children. My dad purchase the house way before he married that lady. I'm Been Told that her children get everything. now that I'm trying to sell the property my father been gone six years and the lady he married been gone almost 5 years. Please anyone is that true. And what can if anything be done