Of Mice and Men is a book that is largely about friendship. Friendship here is not purely straight-forward or simple, but there are a number of instances where George’s care for Lennie is made very clear.
At the opening of the novel, George and Lennie discuss their shared history and the relationship between the two is revealed. George promised Lennie’s Aunt Clara that he would watch after Lennie after her death. The fact that George has essentially taken responsibility for Lennie is the largest indication that George really does care about Lennie’s well-being.
One example of the responsibility that George has taken is seen when George reveals the fact that he has held on to Lennie’s work papers so that Lennie wouldn’t lose them.
This conversation further shows how George is a good friend to Lennie as we see how the two prepare dinner and prepare for sleep. George acts as the older brother, or even the father, to Lennie, telling him stories and cooking his food.
Several moments in the novel also show George reassuring Lennie, calming him down and cheering him up.