Lennie has the mentality of a child and sometimes does not fully understand the questions or may not answer them correctly. George likes to answer for Lennie to make sure that Lennie does not get his information mixed up. In addition, George wants to make sure that Lennie does not reveal their plans to people who cannot be trusted. Finally, some things that Lennie did in the past may be looked down upon or judged by others, so George answers for Lennie to protect him from telling too much about his past.
does not trust him