I do psychological dream interpretation. From a psychological point of view, this dream shows something deep in your heart: on a mountain in your mother's house, it can represent you returning to unmarried state in your dream, and the mountain can symbolize the men in your inner world, especially your father (the father slowly internalizes into the image of all men in your child's heart). I wonder what your relationship with your father was like when you were a child. There are 1 possibilities in this dream, suggesting that your father's love and support were not enough when you were young (before marriage). Later, when you saw your husband and son standing on the opposite mountain and falling down, you felt very anxious and sad. Both husband and son are men, which can also represent the masculinity of your inner world after marriage, such as courage, decisiveness and strong impulse. Husband and son stand on the opposite mountain in your dream, which shows that there is a big "generation gap" between them. This shows that your masculinity didn't develop well when you were young (because you didn't get enough), so even after you got married, you still felt anxious in this respect. The "masculinity" here does not mean that you want to be a man in your heart, but that you subconsciously move towards the balance of yin and yang, the integration and perfection of internal characteristics, that is, to make your heart and personality more perfect. So this dream is a good dream, which has the meaning of reminding you and is a dream of spiritual growth.
If there is really friction and estrangement with your husband and son in real life (this possibility is not too great), then this dream also implies from the shallowest level that you never want to lose them in your heart, so you can only tolerate watching them fall halfway up the mountain and never watch them fall into the valley. Therefore, dreams imply that you are fully capable of making efforts in real life and grasping their feelings.
Pure psychological interpretation of dreams, I hope it will help you!