What evidence does the author give for their respective roles?

WE learn that Lennie was given to his Aunt Clara at a young age. Before she dies, she asked George to take care of him. Thus their roles as caretaker/ guardian (George) and large man child (Lennie) were forged. Lennie follows George's lead like a six year old acting like a six year old does. Lennie is capable of handling massive work loads but incapable of handling the simplest of social interactions. George looks over Lennie constantly. He warns Lennie about dangers and creates back-up plans in the case of inevitable trouble.

Example- Lennie lifts heavy straw on the ranch does work of two men. Lennie, however, gets in trouble but remembers George's back up plan in case of emergency.