Kinship names are the words we use to indicate family members, like mum, mom, dad, aunt etc. Incorrect capitalisation of these names is a huge bugbear of mine. I see it done incorrectly in so many self-published books, and more and more in traditionally published books too.
It seems to cause a lot of confusion, when it’s really actually very simple:
Capitalise when the name immediately precedes a personal name, or when the name is used alone in place of an actual name.
Did you remember to get Mum a birthday card?
We went to see Dad when he was in hospital.
Lily and Joe loved visiting Aunt Susie’s house.
I was seven when I last saw Grandma.
Don’t capitalise when these words follow the personal name, when they don’t refer to a specific person or when they are used with possessive nouns or pronouns.
The Sinfield sisters always stuck together.
There aren’t many dads who would do that.
My aunt wasn’t feeling well.
I bought a card for my mum.
Sally’s grandma lived next door.
Many children’s books portray families and use these terms and I shudder each time I see it done incorrectly. Children learn from the books they read. It’s up to writers and editors to make sure we get it right.