The City Who Fought, by Anne McCaffrey
More re-reading... This is maybe my favorite of the Ship series by Anne McCaffrey.
I really like Simeon. And the name of his brawn is totally escaping me just at the moment! Oh well.
Anyway, this time the brain is a station manager so there's lots more regular people around instead of just the brawn. He gets to be a father which is cool.
There's lots near the end of the book that's just heart-wrenching though. The whole thing with him getting taken out of his column is just scary, but what gets me every time I read this is what he does to get Amos to take care of his brawn since he can't. He very clearly wants to, but isn't physically able.