My mom gets asked that question all the time too and you should see the stunned looks on people's faces when she says she's a never smoker. She has the "same" LC everyone else has. I think most people are looking for a reason, because otherwise LC is too scary. I went through this myself. I never worried about getting LC until Mom was diagnosed, then I was terrified by the idea. It wasn't that I wanted to blame her, but I wanted a reason for her cancer. If there was no reason then it meant I might get it too.
Your husband doesn't "deserve" this any more than my mom does. He didn't do it to himself so I hope he will stop feeling guilty. I don't know what to tell the people who keep asking the question. They don't know anybetter because everyone, including those who should know better (aka the American Cancer Society)keep telling them that LC is a smoker's disease.
Susan