Dr. ABBEY joined the 29th Missouri as the 2nd Assistant
Surgeon in Cape Girardeau and mustered in at Benton
Barracks on September 22, 1862. He died of typhoid
pneumonia aboard the hospital steamer Von Phul on the
Mississippi River enroute to St. Louis from Young's Point,
LA on January 28, 1863.
http://www.angelfire.com/mo2/29mo1/29rstr01.html

As a hospital ship, I would suspect that he was provided a wooden coffin and that the ship had facilities for storage of the dead. Being during the winter months, I would suspect he would have been off-loaded for burial at one of the ports of call up river. I have not been able to find information on the ship's movements at this time or how close they were to St. Louis on the date of his death. Having enrolled at Benton Barracks, I would think he would have been transported to St. Louis.

River miles Vicksburg to St. Louis, 840 Youngs Pt. not too far up river from Vicksburg.