Hi. First of all I get that he's a good provider for his family, but the bottom line is what he's doing is wrong. You don't mention their mum at all.
Is she around? If she is then she should be informed (even if she won't believe it because they're husband and wife). And, you don't necessarily have to tell her face to face, she doesn't even have to know it's you who's telling her.
Yes, please report it! This girl is being taken advantage of, and she doesn't even know it. I can see why that could be another reason not to say anything, but what if your uncle decides to molest her when she's awake next time?
If his daughter found out, from the description you gave us, she probably wouldn't say anything. Just... please report it, your cousin is in danger. You could try to find a helpline that allows to stay anonymous, or if you really really really don't want to report it, then you could do the anonymous e-mail thing, but you have to make sure he absolutely can't trace it back to you.
But that e-mail thing is dangerous, so you should report it. This must be really hard for you, but you have to do the right thing. I really hope everything works out for you and your cousin, And that your pervert uncle is put away (sorry).
X Edit - Oh yeah, and when you report it make sure that you have proof.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.