It seems to me that there are two issues here. The first - was your husband raped? - is a kind of legalistic issue that would depend on points like whether he had the option of declining sex, whether he was forced against his will, and so on. I agree that it looks like this one is a lot more complicated than it looks at first blush. I wonder if there is some history behind your husband's situation.
The other issue is a lot easier - has he been traumatized sexually? Clearly the answer here is yes. If he comes here to talk about it I can guarantee he will be treated with understanding and respect. No one will judge or blame him, and he will be able to just look at the materials here or participate as he feels he wants to and can. He's most welcome and I hope you will convey that message to him.
Nobody living can ever stop me
As I go walking my freedom highway.
Nobody living can make me turn back:
This land was made for you and me. (Woody Guthrie)