The JFK library is best. Its a really good history of his life, presidency and death. His childhood home in brookline is a national historic site but its closed until summer '23. Dont know if it will be open in May. https://www.nps.gov/jofi/index.htm

You can also go to the Massachusetts State House. Theres a JFK memorial there.

If you want to drive 90 min west, there's an eternal flame in Springfield's forest park.