In exchange for food he gave first Nina and then Aaron to the vampires. Seemingly having a change of heart however Jared later attacks the vampires, though is turned in the process.
As a vampire he attacks Aaron, scarring him. He then has a brief flicker of humanity, during which he allows Aaron and Nina to escape.
His status after this encounter is unknown. Though it is presumed that Bernard Senior killed him along with the other vampires.
Jared is mentioned in Aaron's flashback.
Jared is once more mentioned in a flashback of Aaron's.
While Jared was originally meant to have been quite likeable and fun, he seems to have changed upon dealing with the vampires (smiling less and eating less).
Although he gave them away Jared still seems to have cared greatly for his nephew and niece.
Jared seems to have had some basic combat abilities, as he was able to protect Nina and Aaron from zombies.