Neighbor creating problem while construction what action can be taken

Hello, My father in law bought a property with his govt retirement amount. While construction of house, neighbour started creating problem for ventilation and filed a case on us. Infact we have left few place in our area for his ventilation but he says to demolish the house as it's an unapproved land but every house in that area is the same including my neighbor house. Anyhow we won the case and it was dismissed and to be on the safer side we have taken a caveat also. Now we have started constructing in first floor but now again he has put case on upper court. So is there any chance or loop hole for him to stop our construction inspite of we have taken caveat. Please advice