Well, let's see.
On Gettysburg I've read Harry W. Phanz's three volume study on the battle, "Gettysburg" by Stephen Sears, "Gettysburg; A Testing of Courage" by Noah Andre Trudeau, "Retreat from Gettysburg: Lee, Logistics, and the Pennsylvania Campaign" by Kent Masterson Brown, "One Continuous Fight: The Retreat from Gettysburg and the Pursuit of the Army of Northern Virginia, July 4-14, 1863" by Wittternberg, Petruzzi, and Nugent. On Lee I've read Douglas Southall Freeman's biography of Lee as well as his "Lee's Lieutenants", "General Lee's Army: From Victory to Collapse" by Joseph Glatthaar, "Reading the Man: A Portrait of Robert Lee Through His Private Letters" by Elizabeth Brown Pryor, and "Robert E. Lee" by Noah Andre Trudeau. Never hear of "Lee for Dummies".
How about you?
I don’t bandy books with somebody who can’t spell “dog” right.
That's an impressive list..and I'd wager if Lee had health issues he would have likely written to someone about them.