I am not sure from the photos.
If I had no other information on location or culture information, I might guess that the plants had been outdoors whien it was too cold, leading to leaf tissue damage (mesophyll collapse).
Spider mite damage is another possibility. Do you see anything that looks like tiny spider webs on the leaves? Also, try taking a paper towel, moisten with rubbing alcohol, rub the leaves; does it come back tinged with red? If yes, that indicates mites are present. If so, you should use a control method that is specifically intended for spider mites. Pesticides for insects should not necessarily be expected to also take care of spider mites; you need something that works as a miticide. Neem is a relatively benign treatment option, check the label and see if the neem product you can get lists spider mites as a pest that is controlled.
A final option: you mention she lives on the gulf coast. How close to the coast? Get any sea breezes or salt spray there? It could be salt spray damage.
I will offer another suggestion (not asked for). The pot the orchid is in is way too large. Re-pot in a container that is very well drained (many holes) and smaller (maybe half that size) that will barely fit the roots. Use a medium to coarse potting mix, such as "orchid bark".
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