"Do they still have the spacesuits of the other astronauts that were with him on Mercury 7"
No!
Are you sure about that? According to one web site, the Alan Shepard suit is at NASA in Houston. They put the Glenn and Cooper suits at the Air and Space Museum in DC, and Schirra's at the museum in Kansas.
http://aesp.nasa.okstate.edu/fieldguide/pages/spacesuit/
This site also shows the John Glenn suit at the National Air & Space Museum, as well as at least one other Mercury suit.
http://www.nasm.si.edu/collections/space/space.html
The first site also shows NASA with several other astronaut suits from the Mercury program.