My land has been encroached by someone who build a room without permission

Hi I'm Binu, It happened like my father brought a land of 160sq yards somewhere 30yrs ago precisely in 1988. Whenever he tried to build any walls or house in that property, people from neighbourhood told him that its a government land and will be demolished if any structure is built so he didn't. But after so many yrs I got to know about this land and when went see the property, someone has built a structure/room and gave it for rent from past some yrs. The property is still on our name and we have the original documents and also in the government registration site its mentioned on our name. Questions: 1) what should I do to claim back that land and sell it to someone else(What should be my first action steps) 2) Will this be resolved without my father going to court, bcoz its still on my father name. 3) Is there any scope of solving/demolishing the structure without filing a case 3) Is there any chance of that person winning land if a case has been filed in court? Please help me by answering these questions