Can Step brother claim ownership of land after 20 years ?

Hello Layers, Situation is not as simple as it sounds. Let me explain with the background. BACKGROUND: My father had second marriage (in around 60's) after my mother died. We 3 brothers (from my father's first marriage) were teenager when mother died and he married again. When we all three brothers came of age,got married and got separated.Father distributed all his property among: 1. three sons(from first marriage) 2. himself 3. a son from second marriage (who was still a kid) in and around 80's . Now in next 10 years father sold all his lands which was in his name and son from second marriage (who was teenage then) for maintaining expense of home,marriage of 4 daughters(from second marriage) etc. There was one plot which I bought from father which was in name of his son from second marriage.That son was 'Nabalik' at age of 12-13 may be. My father sold that property saying nothing will happen and he has sold others too. Reason being he already took advance for that and was not able to return, also he would anyway sell that to someone else.This was may be 1995. There was proper Registration of plot. I have registration papers ('Kevala' in Bihar) have been paying rents for that land since 20 years.My father is no more, he died in 2010 CURRENT ISSUE: Now, some of my own relatives are pushing my step brother that he has right in that plot and he can sell that or file a case etc. Can my step brother still claim the ownership for that plot/land if he files a case ? Or can he sell that plot with Registration papers prior (to sale) which is 20 years old ? I'm 56 years of age right now I have two sons one is 32 and other 28. My step brother is around 36-38 years. We are resident of North East area of Bihar. What is legal suggestion in this ? What if I transfer that plot to my son , Can my step brother still claim that property ? Thanks a lot