White oak heartwood, is a lot more decay resistant than the sapwood. Most white woods are about as resistant to rot as oak sapwood(not resistant at all)I have some old splits, non bow related, that have been sitting around in my backyard for at least a decade. The sapwood is cactus, powdery and decayed but the heartwood is solid. It doesn't mean it would work for a bow now, but after only a year cut the heartwood could still be viable.
I would remove the sapwood on one stave and make a bow from it. If it doesn't work, then the rest of the splits can be used for windsor chair legs, or other chair parts etc.