Do you know what event(s) or thought(s)/feeling(s) might have triggered this dream? Are your parents divorced? Is their estrangement between your mother's side and your father's side of your family?
Going upstairs=achieving something, getting happy; going back downstairs=returning to reality (ordinary life), also deflation, defeat or depression. Some cold-war between your patriarchal and martriarchal family branches--not really solved by this long-awaited meeting.
To have a good chance of discovering the whole meaning of this dream, we need to determine which parts are the same as in your real life, and which parts are opposite or contrasting from what's actually happening in your divided family. If you will comment on which relations in your family are behaving realistically in the dream in comparison to waking life and your present expectations, we can begin to reach the deeper, more surprising meaning.