Lorcan saw his father get hit with the curse, and something clicked on in his brain. He sent a hex towards the Death Eater, and threw up the most powerful sheild he knew. It wouldn't last, not for long, but it had to be enough. He ignored the pain still thrumming through his nerves, focused on keeping his father alive. He cast a few silent, wand less charms to stop the bleeding, keeping the shield steady as best he could. Rolf would be weak, but he'd survive.
Then his mother was there, helping his father up. Sandy was casting hexes at the Death Eater, and Lori helped as best he could, calling up every bit of Defense he'd studied over the years. He gripped Sandy's hand, drawing strength from his brother and giving it back as best he could.
His mother's Confundo struck the Death Eater, and he stumbled, looking around himself in confusion. "We have to go now," he said, stumbling himself but Sandy was there to catch him.