What additional information is given about James by his father?
If you are referring to Henry Gatz in Chapter 9, he reveals that:
Gatsby "rose to his position in the East."
Gatsby was generous with his father.
They had a falling out at some point, but seem to have reconciled. I get the impression that Gatsby sent money to his parents (his mother is never mentioned).
The most telling piece of information is the Hopalong Cassidy book with young James Gatz's schedule. This is modeled after Ben Franklin's attempt to achieve moral perfection as told in his Autobiography. Franklin created a simlar "schedule of resolves" in an attempt to become a better person later in life. This is one of the many ways he "re-invented" himself, just as James Gatz re-invented himself as Jay Gatsby. What this reveals, however, is that Gatsby, as a romantic idealist, is ill-equipped to survive in the harsh modern world run by the likes of Tom Buchanan. Ben Franklin is not an appropriate role model for a 20th century hero; however, Gatsby exhibits all the qualities of a 19th century Romantic hero. Thus, he is doomed.