Kind of a hard situation to be in. I’ve never really seen a father that wasn’t concerned if his daughter was just getting older at home and not married off.. it’s always something that’s there in the back of a parent’s mind. But I’m guessing they don’t have a close relationship. What about her brothers? Surely there’s an uncle or someone in her life who can reason with him?
Maybe she should just let her brothers and mom know that guy’s side is coming over and “surprise” her dad? If he’s avoiding the idea of them coming over, then that’s all I can really think of, but there’s just no way of knowing if he will get angry by their surprise visit or if he will come around.. it’s risky but she should maybe talk it over with her mom or siblings.
If her mother likes the guy and his family, then she needs to sit down with him and talk seriously. Her dad shouldn’t be ruining a perfectly good rishta for her, unless he has some concerns? She needs to be firm and sit both her parents down and talk to them. That’s the only way.