Dispute on Daan Patra land

I am Central Govt employee, working in Central Excise & Customs Dept, posted in Goa. My native is Jharkhand. I am employed since 2012 in general and since 2017 in this department. I had bought Daan Patra land(Gifted Land) on my wife's name in the year 2016. Now, we want to sell the Daan Patra(Gifted) land, but my eldest brother is creating dispute in this. He is filing case claiming that land is bought by income of Father, so liable to get divided. This amount or property which is on my wife's name is bought by father's income and not mine, is claimed by him. So the person to whom we have planned is sale, is now reluctant to buy fearing any kind of dispute in future. If he files case, it will be huge harassment for we husband & wife, going and coming from Goa to Jharkhand, may be many times. Now we both are working in Govt department, loss of holidays, and expense separately. How to avoid this. Also, we also want my eldest brother to taste this pain, i want him to do up & down from hometown Jharkhand to Goa for some case, I want him to come to Goa and let him feel the harassment, then only he will understand. In case if he files false case and I had to visit Jharkhand, can i file any defamation case against him in Goa, so he also struggle the same. Kindly guide