George takes care of Lennie because he has promised Lennie's Aunt Clara that he will look after him and protect him. This promise and George's moral astuteness bonds the men together. Lennie would not be able to survive outside of an institution if George were not there to ensure his safety. George views his responsibility as a burden at times, but in certain moments throughout the book one may see his true affection for Lennie, particularly through their mutual vision of a farm of their own. This sadly unattainable dream allows them to live outside of the stark reality of their lives. George views Lennie as a brother, friend, and partner in crime. Without Lennie, George would be lonely. It seems as though they need each other equally, although upon first look it seems like Lennie mostly needs George. This makes the ending of the story all the more tragic.