False rape case ipc176 filed against my 14 year old son by neighb

A false rape case was filed against my 14 year old son by my neighbour based on his 5 year olds saying. It seems the incident had happened a month back. During this one month there was no issue at all an his daughter and they were visiting us regularly as nothing had happened. Bail is secured for my son for which a lot of time, efforts and money was spent. My sons medical test was clean. Now that bastard is refusing to let his daughter for the medical test. Based on this and the police statements the case is a dud as chargesheet cannot be filed due lack of evidence. I want to sue him for defamation for 10 times the money I paid for the bail. What is the approx. cost (court fees, any other charges taxes etc. for the claimed amount) that i will incur for the defamation and false allegation suit. Can i defame him on social media and in the society stating that he is using his daughter as a prostitute for extracting money and this is his business. Please help as i had to spend a sleepless week running from pillar to post. Revenge is the ultimate objective.