What is your best one-word description of President Abraham Lincoln's character?

[Rob Wick]

But Lincoln was able to convince Mary to permit Robert to serve admirably on General Grant's staff and that experience launched Robert into success for the rest of his life.

I have no idea how you describe serving "admirably" on Grant's staff when Robert had only arrived in February 1865 and the war ended on April 9, just a few weeks later. He had no time to do anything "admirably." The main highlight of his time was witnessing the surrender of Lee, which he obviously had nothing to do with.

Your comment that serving on Grant's staff "launched Robert into success for the rest of his life" is, to put it kindly, incorrect. If anything launched him into success, it was his own ability, coupled with being Abraham Lincoln's son. Doors that otherwise wouldn't have been open to him were because of who his father was. Although I've never seen any evidence that Robert actively sought these advantages, he certainly didn't reject them once offered.

Best
Rob