Wooden pegs lose pitch

An acquaintance wants to play her grandmother's dulcimer, but says the wooden pegs don't keep the pitch. She figures changing to geared tuners would lose its value (sentimental and possibly antique value). Is this something a luthier could improve or is there something she can do to keep the pitch? She's beginning to think it's only fit to hang on the wall and then buy a modern dulcimer to actually play.