In Chapter 3 Max says Kevin "scared him, but not really." What does he mean?

There is only one character that truly “scares” Max: Max’s criminal father, Kenny “Killer” Kane. Therefore, Max is “not really” scared of Kevin. Kevin does look different than the other kids that Max knows, however. This is what makes Max think about being a bit “scared.” In Chapter 3, Max has retreated into the “down under” of the basement in order to escape Kevin’s current situation due to Max’s “fear.” Max has observed Kevin trying, in vain, to reach a toy up in a tree. Kevin tries, again and again, to jump and hit the toy with his crutch. While sitting in the basement and considering the situation, Max thinks about the “crippled little humanoid” who was trying to retrieve his toy. Max remembers how Kevin called himself “Robot Man” in daycare and wore “shiny braces strapped to his crooked legs.” Even at this point, when the boys were much younger, Max knows that Kevin was not someone to “mess with.” At this point in time, Max is brave enough to conquer his "fear." Why? Kevin needs help retrieving his toy. Max helps Kevin and this begins the friendship.