Do I have a claim

Texas

My father was a poet. He died some decades ago. I see some of his works being sold on websites. I think some of his literary work is being taught in schools. Am I entitled to any form of compensation, and if so how do I make a claim? What is the name of your state (only U.S. law)?

The first question is when were the works written.
The second question is did he sell any or all of the rights?

If you are indeed the successor rights owner, you can certainly attempt to enforce the copyright and keep unauthorized stuff off websites (that is relatively straightforward).

You won't stop nor be compensated for it "being taught in schools." Educational purposes have a pretty broad exemption to copyright.