OK, here's what I can glean from the data.
The hybrid Phalaenopsis Cinnamon Candy was registered by John Ewing of John Ewing Orchids in 1975.
Richard Gilmore of Houston took his particular cultivar 'Valerie' to the SWROGA/South Texas Orchid Society Show and indeed, it received a 75-point HCC from AOS judging.
It is likely that he acquired a plant of the cross, and named it 'Valerie"; he did not "develop" it.
Unfortunately, it is very unlikely that the 'Valerie' cultivar is still in existence, as it would have had to have been passed onto someone else when you grandfather died. About the only suggestion I can make is to contact someone at the Houston Orchid Society, and see if there are any "old timers" that might remember him (I'm assuming he was a member, since he 1. lived in Houston, and 2. was serious enough to show a plant). If so, they might know what happened to his collection.
HOS Contact Info