My son is happily married to a very nice girl. They have three beautiful little girls. We live 10,000 miles away and do not get to see them very often. We call, we write, we send puzzles and games and presents but we do not see them except every year or two, sometimes longer.

I have no complaints against my daughter in law. She is a supurb wife and caring mother. My son adores her as do her children.
In ten years of being married to my son, she has never once called me or asked me, on any occasion, "how are you doing?" After two major operations those words have never been spoken to me by my daughter in law.

I send gifts and cards on her birthday but get no response nor ever a thank you note.

I can not talk to my son about it as I do not want to cause any problems between them. He would not be willing to discuss it with me.

Do I continue to send gifts to her? Am I just being a fool to do anything to have a friendship? I am not sure what to do.
I know that I like her a lot but can not seem to convey that in any way to her.