Grand father's property right?

[anglesey34]

I am 29 years old male. In my family I have one sister (married in 1995) and me and father and Mather. my grand father property comes to my father. In 2003 my mother was expired due to heart problem. After that I have married in 2004. After one year (i.e. 2005) my father has asked and informed to me and our elder people that he is going to marry a women, at that time my father age is 53 years. Before his marriage, we have done partnership registration in (2005-06) and in that partnership deed we have divided and distributed our property in 3 parties. In that deed I got 4 acrs and my sisters got Rs. 60, 000 cash and my father has taken 1 acre. After that I got pass book/patta book from MRO’s office in my name.
After that registration, my father got married (in 2007) and know he is having one son (age 7 years) also.
My doubt is my fathers second wife’s son (first wife’s son is mine) will have any right in my registered property or not?
After major (my brother) If he appeal court to share my registered property then what court should give the decision? What it the best solutions? Kindly give your valuable solutions/suggestion?

I need practical experienced reply

we have made partition registration. it is called partition registration. after the registration i got pass book/title deeds in my name. after that my father married and now my father having 7 years boy.
so total 5 acrs of land. In partition registration i got 4 acr and my father 1 acr. after the registration after one year my father got married. my area is Krishna Dist (Vijayawada). kindly give your valuble good advise.