How does the boss react to Lennies silence?

George attempts to speak for both Lennie and himself, but the boss notices Lennie's silence and questions him directly. Lennie attempts to speak for himself, aping phrases that George has spoken, but sounds completely ridiculous. George tells the boss that Lennie isn't bright, but that he's as strong as a bull and an incredibly hard worker. The boss seems to think that George is taking advantage of Lennie and is willing to take care of him. George tells the boss that Lennie is his cousin and that he promised his mother to look after him. When the boss wonders why they left their last job, George tells him that they were digging a cesspool and completed the work. When the boss leaves, George scolds Lennie for failing to keep completely silent. George admits that he lied about Lennie being his cousin.