Who is T. Sean Collins from World War Z and what is their importance?

T. Sean Collins is a large Texan, who owns a bar in the Special Economic Zone of
the Indies. During the Panic, he worked as a mercenary and was sent to Long Island to guard a high roller. His client invited the largest stars to his estate to wait out the Panic, stocking his mansion with food, water, and energy supplies, as well as 24-hour webcasting.