Explanation: according to Freud's explanation, it is actually caused by human thoughts and behaviors in the subconscious mind. Your mom liked her ex-boyfriend very much. Or because of the reality of some bumps in the road, the two did not come together. She was even misunderstood by her ex-boyfriend, and since then she has always had a shadow in her conscious mind. When she needs to explain or prove something, he is not there. Thus the knot cannot be opened. When one is asleep, this subconscious mind comes to mind. The ex-boyfriend tried to talk to your mom several times, but did not. There are only two answers to this question: one, when they were in the heat of the moment, they didn't express themselves to each other thoroughly. Two, in fact, your mom wanted to say something to him.
Solution; one, she needs more care and communication from your father. Second, increase the time you and your mother to communicate, so that she is pleased to release. Third, more participation in collective life, strengthen physical exercise. Such as square dancing, chess and cards, drinking tea and so on. Fourth, increase nutrition, drink some milk, nutritional products.
I hope my explanation can help you!