If your father has 100% ownership-he can live it to whoever he wants.
If you have made substantial contributions to the property-you might have a special
equity claim-but these claims are rare.
If your father was incompetent or unduly influenced-you might be able to challenge the will.
The answer given does not imply that an attorney-client relationship has been established and your best course of action is to have legal representation in this matter.
Living in the home does not convey ownership to you. When your father dies, the home will either pass by intestatcy (if he dies without a will) or pass according to the terms of his will. Since your father owns the home, he can do whatever he pleases with it.
My practice is limited to the state of Florida. My answer to your question does not establish an attorney-client relationship and should not be construed as legal advice on any subject matter. You should not act or refrain from acting on the basis of any content included in my answer without seeking the appropriate legal advice. You should also be aware that your situation may have time-sensitive issues and you should act accordingly.
As the law varies from one state to another, you should consult an attorney in your jurisdiction for legal advice on your situation.
Mr. Pippen and Ms. Stinson give you good advice. Your rights are neither amplified nor diminished by the fact that you reside with him. Residency does not confer ownership or partial ownership. You can worry all you want as to whether your father will leave the house to your brother, but that is of little moment: Your father gets to decide to whom he wishes to leave his property. If your father is still alive (as appears to be the case since you used the word "if"), you might consider cherishing the time he has left, rather than be preoccupied with what happens to his property after his death.
Good luck to you.
Michael S. Haber is a New York attorney. As such, his responses to posted inquiries, such as the one above, are limited to his understanding of law in the jurisdiction in which he practices and not to any other jurisdiction. In addition, no response to any posted inquiry should be deemed to constitute legal advice, nor to constitute the existence of an attorney/client or other contractual or fiduciary relationship, inasmuch as rendering legal advice involves the ability of the attorney to ask appropriate questions of the person seeking such advice and to thus gather appropriate information. In addition, an attorney/client relationship is formed only by specific agreement. The purpose of this answer is to provide the questioner with general information, not to outline specific legal rights and remedies.
Have you discussed your issue with your father yet? Does your father have a Will in place? If so, has he allowed you to see it or discussed it with you? I find that it is always best to get those sort of issues resolved so no one is trying to interpret what the decedent wanted. Remember that if your father does not have a Will at the time he dies, the homestead will pass in accordance to Florida's intestecy laws. You may want to look at Chapter 733, Florida Statutes.