I gave birth to the child, but my father-in-law insisted on fighting with me to name the child. He also said that if he didn’t name the child by his name, he would not recognize the grandson.

I guess this father-in-law has a weird habit of naming his children! Two methods: 1. Negotiate with the father-in-law to choose a word for each person to form the child's name; 2. The child's household registration name is yours, and ask the father-in-law to name it when you usually call it. When the child grows up, he will still use the name you gave him for life. Don't argue with old people, there's no need.