First off, welcome to SCF!
We do, indeed get a lot of similar inquiries, but won't hold it against you for asking :)
My first advice to you is to use the search button and type in the word "
inherited". There, you will find many threads that address this very thing. If you can't find the answer to your specific question, feel free to ask in the "main stamp collecting" forum.
Secondly, you need to do some homework. If you live in or near a medium to large city, visit a public library and ask for their Scott Catalogues of postage stamps. Most moderate to large sized libraries own at least one set. Most will also allow you to use them in the library only.
Third, relax. In spite of the hype, postage stamps are rarely worth a lot of money. It's possible that your brother collected rare and valuable stamps, but highly unlikely. Postage stamps have been issued by the billions upon billions. Many stamps issued in the 19th century will likely never be worth anything simply because there were so many used.
Remember: you don't have to go too far back in time when the primary means of communication was through hand written letters. There were so many letters written and mailed, that the USPS did not have to change their rates for ~80 years.
Anyways, I'm digressing.
I wish you the best of luck!
Brian