What age difference in an age relationship between an older woman and a younger man is acceptable to you?

A sister in the office next door, 42 years old this year, 166 cm tall, unknown weight, well-maintained body, frequent beauty salon, occasionally gym yoga, fair skin, looks 20+. 4 apartments, 1 Porsche. Her boyfriend is 24, a handsome guy, graduated from a sports school. My sister said her boyfriend has abdominal muscles. During the time when my sister divorced, she was very strong at work, had a bad temper, and dragged her subordinates to work overtime every day. The subordinates complained a lot. In life, she was also unkind, and colleagues avoided her. Since she found her current boyfriend, she has changed completely. The biggest change is that she never works overtime, and she has become gentler. My boyfriend picks me up and drops me off to get off work every day, and he asks me about my well-being on weekdays. He also started to post on WeChat Moments to show off his happiness. In her words, “It doesn’t matter what age gap or brother or sister you have. The key is to be able to look into each other’s eyes and live out your own life.”