Tenancy in common agreement between brother and sister.

I am assuming that this piece of land is in Florida and that your brother resides in FL. Currently, your brother's interest in the land is freely transferable because it is a tenancy-in-common interest. He can sell it or give it to anyone without your permission, in whole or in part. This includes leaving it to someone in a will, or having it pass through state intestacy laws if he dies without a will. Depending upon your brother's estate and estate plan, his wife could be entitled to his interest in the land upon his death. Indeed, depending upon the size of the estate and other details, your brother's wife may be entitled to part or all of your brother's interest in the land as part of her spousal rights of election (regardless of what your brother's will says). Additionally, if the land is in Florida and your brother and his wife live on the land, your brother's interest in the land may be subject to a Homestead Exemption (again, possibly allowing your sister-in-law interest in the land). If you would like to keep your sis-in-law from getting this land, the best way may be for you and your brother to have a lawyer change the form of ownership from a tenancy-in-common to a joint tenancy -- sometimes called "joint tenancy with right of survivorship" or "JTROS" for short. Under this agreement, the owners have equal shares in the property. They are also more restricted in how they can sell or otherwise alienate the property without another owner's permission. Most importantly, in a JTROS, upon the death of one owner, the other owner(s) take(s) the deceased owner's interest in the property. This property interest is automatic and passes outside of probate. Therefore, if you and your brother own the land JTROS and your brother dies before you, you would get your brother's interest in the property automatically (subject to estate taxes) As to your second question: A pre-nuptial agreement is just a special type of contract. It doesn't matter where the parties are physically when they draft or sign it. What matters is whether the contract is enforceable under the law of the jurisdiction where a party seeks to have it enforced. The fact that a contract was produced or agreed to in a foreign country does not per se impact its enforceability in Florida (or any other U.S. jurisdiction). (Or are you asking about seeking to enforce it in Ireland? I know little of Irish law.) Under Florida law, prenups are generally enforceable, so long as there is full disclosure of each party's assets and debts. If assets were hidden or otherwise not disclosed to a party signing a prenup, the non-disclosing party may not be able to enforce it. Additionally, prenuptial agreements must always be entirely in writing and signed. There are many other ways a prenuptial agreement may not be enforceable under regular contract law, including (but not limited to) fraud, duress, and undue influence. For instance: If your brother's wife lied about or misrepresenting assets, debts, or other facts material to the prenup may constitute fraud. If your brother is pressured to sign a prenup on the day of the wedding, that might be evidence of duress. If, prior to signing the prenup, your brother's fiancée keeps him away from you, your family, your brother's friends, and keeps him from getting legal advice, that may constitute undue influence. These are just possibilities and examples. Every case is different; determinations on these issues are fact specific. I advise you to consult with a lawyer, who can look at your specific facts and advise you based upon those facts. DISCLAIMER: The above should not be construed as legal advice or the formation or implication of an attorney-client relationship; it is merely provided for entertainment/educational purposes only. No answer can substitute for in person legal advice from a lawyer who has consulted with you and is familiar with all of the facts of your case.

In addition to above answer. Your question refers to a "tenancy in common agreement". An agreement is different than a deed and if fact you have an agreement-the terms of the agreement would control.

In addition to the prior comments, I would point out that I have reviewed premarital agreements prepared and signed in other states. Generally, these are probably valid between the parties if they were valid at the time the parties signed them. The issue that often comes up is the difference between laws in different states or countries. The agreement might only address the rights that exist between spouses in the other jurisdiction, but not Florida. I have seen some good agreements that give a long list of spousal rights that are being waived, and then it adds language such as, " and all similar rights or causes of action under the laws of any other jurisdiction." It is really a case by case analysis and every situation has its differences. Your concerns show the importance of having a licensed attorney prepare such an agreement, taking the time to discuss all of the facts with the attorney, and then following through on the attorney's advice. My comments are not intended to establish an attorney-client relationship, are not confidential, and are not intended to constitute legal advice. Proper legal advice can only be given by an attorney who agrees to represent you, who reviews the facts of your specific case, who does not have a conflict of interest preventing the representation, and who is licensed as an attorney in the state where the law applies.