Dispute over private pathway

This issue is regarding dispute over a private pathway. the private road connects 3 plots, located one behind the other. the 1st plot belongs to my father which is adjacent to a public pathway and it connects to the main road. our house is built on this plot. behind our house is the 2nd plot which belong's to my father's uncle, where his house is located. the 3rd plot which is behind the uncle's house also belongs to my father. hence 2 parts of the land belongs to my father and one part which lies in the middle belongs to my father's uncle. the public pathway connected only the 1st house to the main road and there was no access to the other two properties. hence both the families agreed to build a pathway by splitting a part of their own properties to connect plot no 2 (uncle's house) and plot no 3 to the public pathway. the agreement was signed through proper legal channel by both the parties and the pathway was constructed. there is another piece of property behind plot no 3 which belongs to our neighbour. since he did not have a path leading up to his land, he requested to buy half cent land from my father from plot no 3 so that the new pathway that was built could be extended up to his property. the financial transaction has been done between my father and the neighbour. now the problem is, my father's uncle is harassing both my father and the neighbour claiming that it is a private pathway and the neighbour has no rights to access the pathway. after the uncle learnt about the fact that the neighbour bought half a cent land from us, he is now demanding a compensation of rupees 2 lakhs from the neighbour, claiming that he also should be paid to use the pathway. i have two questions to ask: 1) is it legal for the neighbour to build a path connecting his property to the pathway owned by the other two families? 2) does my father's uncle have a right to demand money from the neighbour to use the pathway? how should we tackle this issue? your valuable advice would be highly appreciated.