Who is Charles Walter Riley?

I began searching my Mom's family ( and mine, too) a few years ago, but found it very hard to find my maternal Grandma's family.  She never talked much about the Rileys because her father walked out on the family when she was a little girl, and she was adopted by her Uncle Thomas Riley, a police officer who lived in Sunset Park, Brooklyn.  According to Grandma, the Rileys were not really Irish because they were born in England.  Her Grandfather, James Riley, emigrated to New York when he was a child, and fought in the Civil War.  Grandma was named after her Grandmother. 

Grandma's mother, Mary Elizabeth Riley, was born in England, and came to NY as a little girl.  Besides Grandma, Mary Elizabeth had three sons:  Andrew, Thomas, and Harry.  When I would ask Grandma about her brothers, all she would say was 'they were traveling men".  That was true for Uncle Harry:  he was a conductor on the LI Railroad.  Andrew was a printer for Doubleday publishers, and Thomas was a neer do well.

So, when I joined Ancestry.com in 2005, I was very suprised to find my great grandmother's entry in the 1920 Federal Census.  She was living with her three sons:  Harry, Andrew and Charles Walter.  I never heard a word about Charles Walter Riley.  I then did a search on internment.net, and found he was buried in Long Island National Cemetery--same dob as the Charles Walter Riley in the census.

The next step was to write the National Archives in St. Louis, and get Uncle Charlie's service record for WWI--I had found his WWI draft card on ancestry.com.  Well, the record came in a few weeks, and it painted quite a picture of my great Uncle.  He was court martialed in the Fall of 1918 for overstaying his shore leave by 72 hours.  Being a stoker on a troop carrier in the Atlantic must have been pretty stressful, so when the ship docked at Norfolk, VA, I guess Charlie went on one hell of a spree. 

He was released by the end of 1918, after being hospitalized.  I guess he contracted the flu, and got a pardon. 

I just thought it was odd that he lived until 1957 but Grandma never told my Mom or any of us about him.  It made me wonder what other scandals were hidden in the past. Would they explain my family code of repression?