My son married a girl who is not his type. She has a very crude side, swears sometimes, and does not have his level of education. I have gotten used to the idea that they are married and there is nothing I can do other than to be nice to her when she is inside my home. The problem is that she is pregnant now and I am afraid of how she will bring up my grandchildren. She is not basically a bad person, but is very sensitive whenever I offer suggestions. How can I get my son to understand that it is important to think about how they will raise their child and get her to act better, without insulting her?
I sympathize with your very human concern, which reflects what is probably the most prevalent mother-in-law daughter-in-law stereotype, no matter which culture or country we're talking about. What's great in your situation is that both you and your son's wife seem to be making an effort to "accent the positive." That is, despite the obvious faults that you find in her, you try hard to be nice to your daughter-in-law and make her feel welcome in your home.
Even though grandparents know a lot about raising children, they have to remember that each generation is destined (doomed) to learn on their own.
She, probably with her preconceptions of you, nevertheless still shows you that she respects your opinion, and in your own words "is very sensitive whenever I offer suggestions." That shows good intentions on both sides and a desire to make the best of a given situation, which you're right, can't be changed.
In fact one of the saddest situations less realistic mothers-in-law get into is complaining about their daughter or son-in-law in front of their children and grandchildren. This drives a wedge between husband and wife, between parents and children and results in general misery. When a son is forced to choose between his mother and his wife, or a daughter's loyalty to her spouse and her parent, it could lead to complete family dissension
This same down to earth approach, I strongly feel, will, with time and exposure, eventually lead to a mutual appreciation of each others' good points (and which of us doesn't have bad personality quirks), as you learn to like each other. After all you share a very, very important interest -- YOUR SON/HER HUSBAND. Soon, you'll be sharing grandchildren/children -- (Congratulations), and here again your basic common sense will keep you from interfering too much. You'll know how to let them make their own mistakes as young parents, even though with your life experience and good intentions you'd love to help them avoid common pitfalls.
Grandparents are there to support, to encourage, to help -- but not to advise (unless asked), direct or demand.
Try to think back what your relationship once was with your own in-laws, or think of some of your friends or acquaintances who have excellent relationships with their daughters or sons-in-laws, and you'll find that those who consistently think and talk well of the younger generation, the way they're raising the babies and the joy they've added to their life, have better lives; whereas those who are continually complaining, finding fault and trying to "improve" their children's spouse, are avoided.
There's a wise German saying that claims mothers-in-law should engage exclusively in the three "S's": Schweigen (silence), Stutzen (support) and Shenken (gifts).
Good luck as you embark on a very exciting and challenging stage in life -- where you may be less active and prominent, but your input from the background will be very important and, hopefully, rewarding.