Marriage, Divorce and Estar vs. Ser

[tessgold]

Hi, I'm hoping somebody can clear this up for me. I'm learning Spanish using the Pimsleur audiobooks, which are frankly much better than I thought they would be. For the most part they are quite clear, but one of their strengths is also one of their weaknesses. They don't give a lot of explanation, which I usually like, but can occasionally lead to confusion.

Case in point - a few lessons back they were using ESTAR when saying that someone was married or divorced. "Mi hermano está casado." Now they are talking about a woman's brothers and using SER - "Your brothers are married?" = ¿Sus hermanos, son casados?"

I know I must be misunderstanding something, but I'm not sure what.

Thanks,
Tess