How to explain to a woman that a relationship with a man should be built without a child?

A friend met an American man. He came to her from the States, we talked, went for walks, no intimacy.

He invited her to Italy for a week and she happily accepted. Has a daughter 14 years old. She puts him on the fact at the last moment that she will fly in with her daughter. The man blends in.

Six months later, he invites her to meet him at the seaside again. He takes care of the hotel and lodging. She once again makes him promise to stay with her daughter. I think he's getting away with it.

I explain to her that they don't take children on dates. She doesn't understand, stubbornly says that she and the child are one and the same, and when she will have a chance to take her daughter abroad to the sea. My friend is 37, divorced, looking for a husband. How can I change her mind, that at this rate she will not find anyone?