Molly Weasley and James Potter became close after the Prewett twins went to Hogwarts. They became so close that the Weasley kids called James and Lily "Uncle James" and "Auntie Lily." It even got to the point where they didn't even realize that Lily and James weren't biologically related to them because they saw them s much. But it didn't bother Molly because she considered James her little brother.