Last wish of testator as in valid WILL is supreme.
The courts are sensitive towards executing the last wish of testator.
If your father writes a WILL as in your query, It should not succeed for the property as mentioned in your query.
In any case being legal heir you should get notice when a WILL is to be acted upon without any cloud on IT or for probate.
You shall get opportunity.
Approach in person a very able senior LOCAL counsel of unshakable repute and integrity specializing in Testamentary/Civil matters and well versed with latest citations, LOCAL applicable rules/laws/ … and having successful track record…. and worth his/her salt…..and share inputs /show the documents/evidence for a considered opinion..
At each location three are some counsels that specialize in such matters and they are well known.
Check for such counsels at LOCAL civil courts, HC, SC……
Is the WILL registered?
Are the witnesses unshakable?
A registered WILL is not easily set aside atleast on counts of authenticity.