Dave is a man who is very naive to the world and people around him. He lived a very sheltered and introverted life in Chicago, only really open to speak to people he gets to know but not necessarily shut out from speaking to others. He would have a strong tendency to just listen to what people have to say, and take it as fact at face value nearly every time without really questioning whether or not they had an ulterior motive or were lying to his face.
Before the outbreak, he was the type of guy to just go to school, go home, do his homework, play some online games, and on rarer occasions go out to hang out with friends. He and his friends would often get him into mischief, like stealing a candy bar from the gas station. He never would steal on his own, but he's a very malleable individual. A couple shoves into any direction will steer him into that path.
Since his parents were enforcers of his introverted nature; strict and intolerant, they thought the best way to set him straight was to send him to his grandma's place back in Chernarus to put distance between his friends. Unbeknownst to him, when he arrived the beginning of the steps leading towards the outbreak had already begun. It wasn't long before he caught wind of what might be happening; increased military personal, curfews, people wearing hazmat suits and the sorts, and he was encouraged by his grandma to leave town before he could get hurt. It would end up being his biggest regret to leave her behind, and as all communications eventually dropped and there was no way in or out of Chernarus, he decided the best thing he could do is at the very minimum fulfill his parents' wishes of not being the candy-stealing fool that he was when he was sent here. In addition to surviving, he hopes to help as many people as he can.