I think this is a very normal thing. This child is yours, not hers. Although grandma also attaches great importance to her grandson, she is definitely inferior to her son in her eyes. Isn't it normal for a mother to miss her son? I think I can understand.
one: decades of mother-child affection
You should know that before your mother-in-law came to help you take care of your children, she and your husband had a mother-child relationship for decades. She raised your husband with one hand, and the affection between the two people is naturally good, which is a very normal thing. I'm sure that no one can compare with his son in her heart. But this doesn't mean that she doesn't love her grandson. These are two things.
two: when everyone has a lip service
whether we are adults or children, we may have a lip service, that is, we speak too fast, or sometimes we come out without thinking. What's more, your mother-in-law is so old, so it's normal for her to call her by the wrong name. Why bother to haggle over every ounce with this matter? It's not a big deal.
Three: Learn to understand and learn to tolerate
Actually, I think when two people get along, they should learn to understand and tolerate. Now that you are a mother, you should be able to appreciate her love for your children. I don't think it's a big deal to talk about my son's name. Sometimes we do like to use the address of adults instead of children. If you really mind, then you can just tell her not to do this.
in a word, I don't think it's a big deal, so it's not worth discussing. As long as your family gets along well, I think this is more important than anything else. Names are just floating clouds, not important, just be happy.