It’s possible her mother was not nurturing and your mother did feel unloved. Her mother’s generation did tend to be cold and children were to be seen and not heard. Is it just the two of them or did your mother have other siblings? Is your aunt older or younger than your mother?

Your mother may unknowingly be replicating the relationship she had with her mother in the way she relates to you. People do tend to pick up communication styles from their parents along with generational messages.

Complaints often mean “mom never taught me to...” and her mother’s generation often lacked in communication skills.