Actually, what happened to your cousin is not as obvious as you said. There are other reasons why she is unhappy in the new store, but she says there is a generation gap between her new colleagues and she is hypocritical to others. It is likely that a new colleague was cold when the child first arrived, or that the child was criticized or dissuaded by the new colleague when he was full of good hopes for the new working environment, resulting in inadaptability to the new environment.
As long as your cousin realizes her real reason, deliberately avoids the person she thinks is dissatisfied with herself, and even actively communicates with that person, the problem will be alleviated. Maybe it won't be long before she sees the smile and concern of her new colleague, and the situation will naturally improve.