That's a very good question. I'm not a Mormon so I guess I wouldn't be the right person to answer this, but as a Christian I can give my personal advice. 
 
I have in-laws exactly like this, and the only thing you can do is turn the other cheek, treat them as respectively as you would want them to treat you, and don't give in to their bullying.  
 
I know it seems hard and you wish you could just fix everything, but this is not the kind of reasoning that would lead someone to church. You could confront them perhaps, tell them exactly how you feel and that you wish they'd just be nice to you. 
 
Hope this helps.