The provisions of Indian Succession Act apply to the Christians and under that law, there is no concept of ancestral property; this is restricted to Hindu succession.
Anyhow, the issue in the instant case is limited to the 2000 sq.ft. of property which has been bequeathed to the original author. The posted suggest it to be self acquired property. As such the only question is whether the Will is valid. Already a civil case is pending. Let the Court decide the matter on merits.