The rules vary from place to place, but in public, people can usually be tape-recorded without their knowledge or consent. There are exceptions, of course., e.g. courtrooms, some types of government hearings, and the list goes on.
In a private place such as your home you can expect that no one will audio record your conversttions, unless the government gets a warrant, and even then the restrictions on time for such recordings exist.
Finally, it depends on the circumstances or the recordings and whether or not those circumstances would constitute a "reasonable expectation of privacy." For example, your brother was recorded giving a public speech. There is nothing illegal about that recording because of the public nature of the place. If the discussion was just between the two in a private place like the home, then that would likely change the rules. Check with a lawyer with details to be sure.
Good luck to you.
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In my state of NJ a recording may be made if one person knows it is being done. Such transcripts can be used in court as evidence. In certain cases recording a telephone conversation especially from two different states is a federal offense. You were smart not to record the converstion. Do you remember Monica Lewisky? Her "friend" Linda Tripp recorded some of their phone conversations. Monica lived in DC and Linda lived in MD. The recording is permitted in DC but is a crime in MD. As a matter of fact the Attorney General of MD did charge Linda Tripp with a crime, but decided not to prosecute.
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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 an attorney in their own state to acquire more information.