From the perspective of western theory, this dream mainly reflects your concern for your sister. On the one hand, you recall "if only your brother-in-law had repented before", on the other hand, you may hope that a good person can treat your sister and children well. The wine in the dream suggests that you are helpless about the status quo, and it means a little to drown your sorrows.
From the perspective of oriental theory, it may be that my brother-in-law said goodbye in a dream, and I hope you will take good care of your sister and children. He may be reborn.
I hope it helps you.