It's a fruit all right, but not a dragon fruit/pitiya. Notice your cacti's leaves are flat and doesn't have a thick triangle shape leaf/stem. If, the flowers only blooms at night, it's most likely a "queen of the night/Dutchman's pipe"(Epiphyllum oxypetalum) But, on closer look the leaves, look different, yours kinda have serrated edges, my mom's plant, have smooth edges. It's probably some other kind of orchid cactus in the epiphyllum(most of these are hybrids and flower in the daytime or at dusk/dawn, but some will flower at night too like the E. oxypetalum) genus/family? All will produce fruit, if the flowers gets pollinated, either by hand or naturally by pollinators. As far as I understand, is that all cacti/us's fruits are edible. Though some are not very tasty, very bland and watery flavors. Like your orchid cactus fruit there. You can try it, to see if you like the flavor, though, I bet it's not very sweet or flavorful.
Since you're in Fl, lots of the members over there could help you out with a few cuttings from their DF. Ask around on the forum in this thread and for a quicker response ask in the wanted/buy/sell section, but if you can't locate some locally, I can ship you a cutting or two for postage fees.