I would like more information about my 3rd Great Grandfather. He shows up as enlisting in the civil war, but does not show up in further censuses.

I have a newspaper article from the Patriot News in Harrisburg that appears to have political intervention in order for his widow (my grandmother) to get benefits.

a) is this normal?
b) is there a way to get more information about my 3rd Great Grandfathers military service?