Im 16 years old . Can you help me with something please?

My family is almost traditional, but they love my brother very much. My brother is someone who has not achieved much success in his life and has failed most of the time and now he is gambling on the biggest event of his life. He is in a relationship with a woman who is older than him (as I said, my father is a bit traditional and is not happy with this), and is socially inferior to our family and has an average job, and says that he wants to get married. This lady does not match my brother in any way, even in terms of appearance, because she is about 30 or 40 centimeters shorter than him. My mother is very upset about this, but my brother does not like to see some facts. For example, this woman returned to her workplace a long time ago and said that I am going to get married and I don't want to come to work anymore (at that time, even my family didn't know that my brother was so serious about marriage). She even counted on the shop and house that my father left for my brother

what can I really do?😭.