How do you deal with in-laws?

My father in law passed away a few months before our wedding, my mother in law is an exceptional woman. I totally adore her. She lives next door to us, but never bothers us (never comes over uninvited). She doesn't meddle, and always has something nice to say to me. She's wonderful!

I am glad that I have only parents-in-law....my husband is now an only son because his brother passed away. My MIL, irks! she dislikes me very much, because she wants his son, my husband, back! And they are not living together with my father-in-law and she always advice my husband, every time we had problems, to get rid of me because she thinks that it is the most convenient way to solve family life, she wants us to go separate ways, like she did in her marriage life.whew!And she always mends with our life! But my father-in-law, is very civil to us. I know somehow he had ill feelings with me because what my MIL always tells about me. Maybe, God gave me that kind of woman because He knows that I can somehow deal with it!

My in-laws are great. Highly educated, my father in-law is a retired doctor and now studies philosophy. My mother-in-law is a table tennis champion and she is hard worker. She is specialist lace-maker.

I have a friend who recently got married. She is as we say 'rich' while the guy also has enough but he supports his family in everything. Now my friend doesn't get along with the in-laws too much, I can't help but wonder. I think it's part of my friend's attitude or a clash of personality. I have personally met the mother-in-law, she's not that great but she isn't that bad either. She is somewhat frank and she tries hard to get close to her but I think the mother-in-law feels that my friend doesn't like her. As a friend, what should I advise my friend? She's new in the family and her husband works overseas, so she's more in contact with the in-laws and alone but she don't live with the in-laws.