Louise Fletcher? Is it The Magician of Lublin? That’s the only WWII movie I know about from her and I know little about it.
Ok here is a film I have tried to find for years. About a man in his forties or fifties who is involved with a young twenty year old. He is about the same age as the girl’s mother, and at the end, it is suggested that mom is dying and she is happy that the man will be marrying her daughter and caring for her.