How does Calvin fit in with the Murry family?

Calvin, the
gangling, orange-haired, blue-eyed teenager who accompanies Meg and Charles Wallace on their
journey to rescue Mr. Murray, fits in well with the Murry family, almost as if he is one of
them. At their first meeting, he tells Charles Wallace and Meg that he once in awhile feels a
"compulsion" to do things and that he obeys the compulsion. He had a feeling on that
day that he should go over to the haunted house near the Murrys' home, and in doing so, he
encountered Meg and Charles Wallace. After some initial sparring, Charles Wallace invites him to
dinner, saying he wants to trust him. For Calvin, the Murrys provide a warm and nurturing
environment that is different from his own large and overburdened family.