Jessika,
In your thread "My Story" you wrote:
Married and pregnant at 17, gave birth at 18, son at 2 days old almost died, he is ok now, divorced at 20, started stripping at 20, on drugs and alcohol really bad at 21, off drugs and out of stripping by age 26--which is where I am now.
I can understand that your MIL is worried for her grandson, particularly in view of what he has gone through.
Does your MIL realise that you are now off the booze and drugs? Does she understand that you have cleaned up your life? And to what extent?
I know I'm being the devil's advocate here, but why is it so evil that she shares with her grandson some of her values and beliefs? Would it be any different if she was a Catholic, or a Muslem?
I know you haven't been able to give us the whole story, but I am sure she has feelings too, and I dare say she really loves your son, just as much as he loves her.
I hope you are able to come to some agreement, without your son getting hurt in the process.