It's a bad sign when your mother writes you and quotes scripture. Lots of people here, self included, are feeling your pain. My parents have passed without knowing I'm an unbeliever. My wife's mother is still guilt tripping her.
Mom in law wrote to dear wifey how sad she'll be in the "new order" when her daughter is not around. It's easy to write in euphemism's. What she really meant to say is that she'll be gloating about how she was "right" and her daughter was "wrong."
To put it even more plainly, the god of love that she worships will have killed a loving and devoted daughter, mom, wife and sister in order to prove he is righteous, and to avoid contaminating all the true believers left on earth after armageddon.
That this belief system is beyond disgusting goes without saying. While I'm sincerely sorry for your loss, you are forever releasing your children from such sick and destructive thinking. Take some comfort in that thought.