Demarcation of land falls within revenue jurisdiction, where you have already stated to have filed a case, can you not wait for the outcome of the same ?
Even then if you so desire, yes, you can flle a suit for declaration, permanent and mandatory injunction against your neighbour, who have encroached upon the land purchased by your deceased father.
Why do you not move to the High Court for a writ of mandamus and/or necessary directions to autorities concerned and the encroachers under Article 226 and 227 of the Constitution of India ?
So impatient ???