Kids are 17 and 12. Mom/grandma passed away a few year ago, and grandpa immediately married his new wife. There is a long story there. Dad/grandpa wants us to treat her as if she were grandma, but I have a hard time doing that. My kids had a grandma that loved them so much. New wife has no role whatsoever in kids life, other than showing up at family events 1-2 times per year. She is not my mom, so why would she be the kids grandmother? It is causing a conflict, and am hoping someone has a suggestion on what to call her, other than grandma or Miss "Kate". Thanks in advance.
Perhaps some other name that implies familiarity and closeness, but has no actual meaning to your kids: mima, grammie, G-K (for Grandma Kate) come to mind. If culture/nationality is important to you and/or your kids and/or your dad and/or his new wife, perhaps a non-native language word for grandmother, e.g. I know of an American family that, in order to honor their Swedish heritage, refers to their grandmother as mormor. For them, it actually is a term of endearment, but for your kids, it could have its own special meaning.