By Emma Rowbottom A boy has been left heartbroken after a Thanksgiving gift from a friend revealed more than he bargained for. With his friend buying DNA kits for their entire friendship group, the boy wasn’t prepared for the astonishing results, with a family fiasco unfolding after he found out a dark secret that he couldn’t ignore. He said: “For as long as I can remember, my parents’ marriage has been happy and stable. They were high school sweethearts and my dad proposed to her at their senior prom, or so they say. Nowadays they’re your stereotypical old couple, just as in love as the day t…