"All right. So more like biological family than, say, brothers in arms," he says with a nod. "Sorry you had to leave him behind."

Since, you know. Presumably twins are especially close. He and his own brother have been compared so many times as looking alike, and for a time they certainly had been very close, but that was back when they were kids and didn't have much of anyone else to depend on. They couldn't be more unlike each other, otherwise.