I'm upset my MIL won't make a "family quilt" for me and my husband
why won't your mother in law make you and your husband a family quilt?
because my husband and I have no kids
You need to be more understanding of your mother in law's reasons for not wanting to make a quilt. Making a quilt is a big undertaking and you should not put pressure on her to do something that she does not want to do.
fine. however when I don't know how to care for children, I will blame her for that as well.
Have you tried talking to your MIL about how her decision makes you feel? She might be more open to making you and your husband a quilt if she knows that it upsets you that she won't make one. This would also give her a chance to explain her reasoning.