You can get a VA "In Memory" marker and place in a cemetery. As long as you can show he died in Okalona, and there is evidence that tells of the dead being buried nearby. You have to provide much info as to how hospital burials were conducted because they want to do everything they can to discourage you. But if you persist it can be done. I believe I have rec'd such a stone for a soldier also died at Okalona and buried there. If you run in to snags, let me know and I will dig out my "proof" I always send with a hospital death and burial in a Confederate cemetary that has no records for burials.