I could have sworn that Barnabas was a Revolutionary War vet. He did have that big gaudy medal in the portrait. Maybe I'm thinking of fan fiction though.
I think there was reference to Thaddeus Collins dying in the Civil War, presumably this was Tad, which explains why the Collins fortune passed to Edith after Quentin's death ( there's a huge story there, the gap between 1840 and 1897, and I've read two very good and different fan fics about the 1870s)