One reason your relative may have joined the 45th KY Inf. was because he was drafted by the U.S. Army. The draft was an attempt by the Yankees to force an allegiance from the many idle Kentucky men who no longer had access to Confederate units due to Union occupation and to thwart them from possibly being conscripted by roving Confederate bands. I had a number of relatives that served in the 5th KY Inf. (CSA) and those that returned to their homes after the regiment disbanded in Oct. 1862, were issued draft notices in the summer of 1863. One of the relatives is said to have been forced to join at the point of a pistol. Another had just been exchanged from a Union prison. Others received their draft notice, but were part of other CSA units and of course paid no heed. The 45th was made up of many "galvanized Yankees" which was the term given to former Rebels who were now in the Union ranks.