I tend to think that George resembles a father in that he constantly feels the need to take care of Lennie. There is an ethical responsibility that George feels for Lennie. George tends to Lennie as a father would a child. George feels that he is the sole provider for Lennie. There is frustration that he experiences about the need to constantly tend to Lennie and deal with all that he has to regarding Lennie. Like a father to a child, Lennie exacts complete and total responsibility from George. George understands that there is a very good chance that if Lennie were left alone, bad things usually happen. This was the case in Weed. This is also the case with how Lennie winds up alone with Curley's wife. George is like a parent for Lennie because he understands clearly what will happen when he is left to his own devices. It is for this reason that George takes the action he does at the end of the work. He ends up taking Lennie's life with a sense of dignity and devotion, such as a father who ends up mercifully taking the life of a child.