Inheritance

My mother and father got married in 1984. I was born in 1988. Only child. They acquired a property in 1995. This is our family house and registered under my mother's name. She died a couple of years ago. Recently, I found out that my father had an affair with another woman in 2002 and they had a child.i am not sure if the child was named after my father. Now, this other woman and my father want to live together. She has 3 other kids with her previous partner. She forces my father to adopt her children. If my father marries this woman and adopt her children,what will happen to the said property in terms of inheritance? Thank you in advance.