It can't be done. Sorry.I assume that they won't let you buy a recorder for him. If so, have him wrote what he wants to say in a journal or notebook, or get the prison librarian to help with that.
The record deck is known as a PS-LK47P.
If you wish, another deck will work as long as it has a magnetic cartridge and no preamp built in.
A Technics SL-1200 is the sort that is fine and a definate upgrade.