What does Winston dream about? What does it tell us about him?
In 1984, Winston dreams about a few things. One of his dreams features a dark-haired woman running toward Winston. Winston sees it as an act of freedom and Party defiance. This is going to sound cliche, but I think it means that Winston is a lover, not a fighter. Bear with me. It's clear through the book that Winston does not like the Party and seeks to find ways to subvert its control. One way is through his sexual relationship with Julia. Hence the lover part. His other tactics are non-confrontational: writing secret thoughts in his journal, renting a room, etc. None of that is a violent step against the party. Hence the not a fighter. Also, if Winston was more of an anti-party agent, then the dream might have been about him running naked and destroying the party.
Along the "anti-party" dreams, Winston has a dream with a voice that tells him that they will "meet in a place where there is not darkness." Winston thinks it's O'Brien's voice.
The third dream sequence is about his mother and sister. In the dream they are on some kind of ship, and Winston is not on the ship. He is an outside observer to their plight. The ship is sinking, and Winston knows that they are going to die on that ship.
"He was out in the light and air while they were being sucked down to death, and they were down there because he was up here. He knew it and they knew it, and he could see the knowledge in their faces."
The dream represents Winston's guilt. When Winston was still a boy, living at home, he would take extra food. Taking extra food meant that someone in his family was getting less food. During one such event, his mother begged him to give back the food. Instead Winston ran out of the house, and that was the last time that he saw his mom and sister. Winston feels guilty about it now, and believes that his selfishness played a part in their disappearance. The dream is simply another rendition of those events.