He was originally Hiram Ulysses Grant, but his family called him Ulysses. Then he enlisted in the war and was registered as Ulysses Simpson Grant , with his mother's maiden name after that he decided to leave it Ulysses S. Grant.
He didn't. When Hiram Ulysses Grant entered West Point a mistake was made and he was enrolled under the name of Ulysses Simpson Grant. He kept the name and later became known as unconditional surrender Grant or U S Grant.
Probably not. Grant did get drunk on occasion when he was a young man, stationed in California far away from his family. After the Civil War began and he resumed his military career he drank very little if at all.
From 1860 to 1861, Ulysses S. Grant lived with his family in Galena, Illinois. He later moved to Springfield and Cairo in 1861 during the Civil War. In 1865, after the end of the war, he moved back to Galena.