Sorry to hear about your grandmother, my condolences.
A lot of good ideas so far, another may be to donate them to Balboa Park as they display blooming orchids throughout their
Botanical Building and have a greenhouse to house the orchids when not in bloom. If there are many Cattleyas, Dendrobiums or other temperature tolerant genus' then maybe a botanical garden with a tropical/subtropical section such as
Quail Botanical Gardens where they can be mounted on trees. Searching for universities in the area with botanical programs may prove to be beneficial as well.