My son (who is 2 years old) right on my father property

Hello Sir, I am 38 years old from Hyderabad and my father is 70+ year, as my dad has three property (two of them are open plots and one is house) all of them are earned by him (self-earned). Will my son has rights on those property as he is 2 years old as for today. I just wanted you to know that I and my sister are having kid's of my dad’s first wife and we have a brother who is my step mother ( she is my mothers own sister) son. As we all belong to my dad’s kids. 1. I was eager to know that my son's has the right or not. 2. The house which my dad and his second wife are living, has a rental part (it has three rooms) in which I have taken one of the room and paying the rent for it. now I am pleading my dad to construct the house by demolishing it and making me as co-owner as I am salaried and get the loan and build the house for them as well as for me. But my setp mom asking me to give 40lac to build the house and to making me as co-owner. As I am worried what to do?