Nobody is automatically entitled to any share in a person’s self-acquired property. Your father can sell or lease it to someone, gift it away, will it to anybody, etc. It’s only if he were to die intestate—without making a will—that certain people would become entitled to a share in the property in their capacity as heirs. Such a property—belonging to a male Hindu dying intestate—devolves on his heirs as per Section 8 of the Hindu Succession Act:
“(a) firstly, upon the heirs, being the relatives specified in class I of the Schedule;
(b) secondly, if there is no heir of class I, then upon the heirs, being the relatives specified in class II of the Schedule;
(c) thirdly, if there is no heir of any of the two classes, then upon the agnates of the deceased; and
(d) lastly, if there is no agnate, then upon the cognates of the deceased.”
You are a Class 1 heir and would be entitled to an automatic share if your father were to die intestate (without leaving a will)—and an affidavit disowning you won’t affect this right—but under no other circumstances.
You are not entitled to anything as far as his income is concerned.
Please clarify as to what do you mean when you say the property was divided between you and your brother at the time of purchase.