What has George told Lennie about that he always remembers even when he forgets everything else?
George reminds Lennie to "hide in the brush 'til I [he] come[s]". This order foreshadows that Lennie will inevitably get in some sort of trouble apart from other incidents in the novel. George and Lennie constantly must run from different ranches and authorities because Lennie gets in trouble due to his childlike mind and superhuman strength. Lennie repeats this order to himself throughout the text, which is important because he is unable to remember most things. Finally, Lennie does hide in the brush, waiting for George tp rescue him yet again.
Lennie always remembers his aspiration to tend to the rabbits on the farm that him and George will share one when he forgets everything else. This is dream that George tells Lennie all the time to comfort him especially since Lennie has a love for bunnies or really anything soft. This is how Lennie copes with moving around so much from farm to farm. This dream gives Lennie motivation in life.
Lennie always remembers their dream about owning a farm. He is excited that he gets to tend to the rabbits.
George always tells Lennie about their "dream". George and Lennie's dream is to have there own farm and have rabbits so that Lennie can pet them because he likes to pet things(although he always ends up killing them). This is a dream that the men see as a fantasy or something to look forward to in their future.
Hope this is the answer you're looking for!