Yellowing orchard cacti
From just the pictures I can't tell you what is causing the problem with your orchid cactus but it does not look like a disease or insects. Could they have been exposed to low temperatures? Or touched a cold window? Was something sprayed on them inadvertently? Since you live in Windham County, you can contact the UConn Master Gardeners at the Extension Center in Brooklyn. Perhaps you could bring the plant to them to look at. Their number is (860) 774-9600. Except for the fact that I can say your plant is several years old, I know of no way to determine its age.
Thank you for your help