Ben Carson's claim was in his 1995 book "Gifted Hands".
General Westmoreland died in 2005.
Perhaps some other ad hominem would work for you?
I’ve heard him say that “some people” said he could get in West Point “real easy”, to him saying “representatives” told him, to him claiming Westmoreland personally told him. Who will it be today? O’Reilly got him to admit last night that he was never offered anything. O’Reilly pushed him on it and told him maybe his wording could have been a little different in the book and Carson agreed with him. But of course not before saying “well that’s how I took it”. In other words he lied in his books. If Carson is such a smart man, why did he personally mislead people for years into thinking he was offered a full “scholarship” to West Point. I’ve also noticed he never misses a beat to tell someone how smart he was as a kid and how he did things faster than anyone else so of course the world was impressed with his genius. He reminds of Steve Urkel, the nerdy black kid who couldn’t find a girl friend but was always the teacher’s pet, and 50 years later he’s not changed.