You say all your cousins are out of da troof now, I'm thinking they were all raised in the lie, so my response would be " just like your children, I've decided to use the brain that Jehovah gave and did my research on the Organization and found out there are many things the JWs teach that just don't add up, for example, just about everyone knows the JWs don't take blood, but now it's acceptable to take blood fractions, the Bible has never changed, so what scripture says after all these decades it is now OK for JWs to take blood fractions?" So many other things I could mention to you, if you'd like me to go over a few things with you that don't add up within the JWs just let me know, thanks".
There are so many things you can point out to her, but of course if you wrote the above to her you would never hear back from her, the folks in the truth can't deal with the truth.