what is RTS appeal? Jurisdiction?

Learned advocates,

one of my friends father had a property of around 10000 sq.ft his father had 4 children including him,
(2 brother 2 sister)

1 of his brother by doing false signatures acquired all the land, and the other 3 residing out of India were not aware about the same

Now they want to get the shares in property. They were advised to file RTS APPEAL, now what is RTS APPEAL, where can one find the provisions?? , what is the jurisdiction??? Is there any other way out

Thanks in advance