Why was Brian so calm about him being alone forever?

Brian wasn't always calm, in fact, he once tried to kill himself after a plane flew overhead, and he wasn't able togain its attention. Adversity makes Brian strong, his failed attempt at suicide gave him a new reason for living. Brian makes mistakes with each new day, but he also makes strides in maintaining his own survival. He's calm because he's finally taken his fate into his own hands...... he's calm because he's willing to do whatever it takes to survive.