George lies to the boss because if he realizes that Lennie’s mental deficiency is a threat they won’t get the job.
George lies and tells the boss that Lennie is his cousin, and that they left the job in Weed because it was done. George tells the boss that Lennie is not smart, but does not tell him he’s mentally challenged.
When the men arrive at the ranch, they are already in trouble because they were late. The boss is not happy about it. He asks them questions, but only George answers them. The boss begins to get suspicious.
George broke in loudly, "Oh! I ain't saying he's bright. He ain't. But I say he's a God damn good worker. He can put up a four hundred pound bale." (ch 2)
The boos thinks that Gerge might be taking Lennie’s pay because he is talking for Lennie. He assumes that since George seems to be in control, he is taking advantage of Lennie.
George has to be careful, because if he annoys the boss they might not get the job. He needs to walk the fine line of protecting Lennie and not making it seem like he needs protection. If Lennie is mentally challenged, the boss might not want him to work.
George finally makes up a story that he thinks the boss will buy.
"He's my... cousin. I told his old lady I'd take care of him. He got kicked in the head by a horse when he was a kid. He's awright. Just ain't bright. But he can do anything you tell him." (ch 2)
The boss finally concedes that “he don't need any brains to buck barley bags” (ch 2). When George tells him they left because the job was done, he seems to accept the explanation. He warns George not to pull anything over on him, telling him that they better not be wise guys.
George’s relationship with Lennie is an unusual one. This situation is an example of how George is constantly on the defensive. He never knows what Lennie is going to do, and what trouble they are about to get into. It cannot be easy for George, and he sometimes has to stretch the truth to protect Lennie