If your father wrote a will then what he designated in his will is what happens to his money.
He has the legal right to give his money to whomever he wants.
If there is no will, his assets follow the rules for PR intestate succession which normally means his surviving spouse and all his surviving children share in his assets. In some cultures the oldest surviving son would automatically inherit the land and any titles. This is usually not the case in America or in most modern democracies. You might find my legal guide on selecting and hiring a lawyer helpful.
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(Even if you are not filing a lawsuit this information can be useful).
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You might find my legal guide on Estate Litigation (with a will) helpful.
You might find my legal guide on Estate litigation (without a will) helpful.
LEGAL DISCLAIMER
Mr. Sarno is licensed to practice law in NJ and NY. His response here is not legal advice and does not create an attorney/ client relationship. The response is in the form of legal education and is intended to provide general information about the matter in question. Many times the questioner may leave out details which would make the reply unsuitable. Mr. Sarno strongly advises the questioner to confer with a local attorney about this issue.
I agree with Mr. Sarno. No one can tell you what your rights are without knowing whether there is a will, a trust, or any other document that would bear on the situation, such as the manner in which he held title to real property or financial institution accounts. You would need to provide considerably more information. If you really want a definitive answer, then you need to retain counsel and go over all of the details and/or authorize the attorney to find out the details.