That’s not true. Brennan gave a reasonably close description at the scene. And singled out LHO at the lineup later that evening as looking like the gunman. (And that’s what I said that you disagreed with.)
“Reasonably close”? It was the wrong height, wrong weight, wrong age, and wrong clothing to be Oswald. He also had no reasonable way to estimate those things for a person “taking aim” for the last shot, who would necessarily be crouched down behind boxes.