for a history of his unit, try this link

http://cdl.library.cornell.edu/moa/browse.monographs/waro.html

It opens the web site for the "The War of the Rebellion" official records--this is the collection of all official military records for both sides--action reports, correspondence, etc. You can use the search function for the unit your man was in and follow its combat role, find the unit roster, etc. Very useful site and its is FREE!