I happened upon your post about Charles Cary Ewer by accident. I did try to e-mail you, but thought it might be safer to post as well.
I'm a descendant of Charles Cary Ewer and have a fair bit of information about him that my cousin collected about his ancestors - and those of Henry Ewer. My only problem is that I don't have these to hand just now, but will see them again in about a month. (I'm not going to go into these just now in case I am remembering wrongly, but I'm pretty sure they go back a long way before Henry Ewer. Of course, whether the 'facts' will be detailed enough to satisfy you is another question!)
I haven't actually been working on this part of the family so it's not absolutely at the forefront of my mind, however, I do have a Family Bible from which I remember the names Polly Crowell and Orinda Case. And I would be happy to scan these pages for you since I imagine they would be of interest to your husband's family.
Although, I don't have much with me at the moment, I do have here, on this computer, two photos of Charles Cary Ewer - one in his Civil War uniform. My cousin has transcribed a long letter which Charles wrote home during the war to his family and I think this might be of interest to you, also, as it mentions Henry Ewer's illness - he was the one who died during the Civil War.
Charles Cary Ewer was wounded (the wounds are thought to have caused his early death) and went to Washington where he married my great grandmother and had two little girls. He was quite well known as a soloist in Washington and I have his score of 'Creation' and also, I think, a program.