So, this is Natasha, and this is Josh Summers, currently 27. He's a last-name character from the Harry Potter books who tried to cross the age line during Harry Potter and the Goblet of Fire. He was a Hufflepuff, a year behind the Trio, and generally a very typical Hufflepuff. Hard-working, steady, and loyal. He's chivalrous to a fault and hates confrontation 99% of the time (the 1% he won't back down on are his healer's ethics).
He was a member of a future healer's group at Hogwarts which became basically the underground medical arm at Hogwarts during Deathly Hallows and dated Emilia Spinnet during that time. He wasn't a fighter, but worked really hard to try to patch up his friends and the Dumbledore's Army types. A sixteen-year-old should not be convinced his friends lives and limbs depend on him, but, you know, war. He had some bitter opinions about what he saw as collaborators. After he finished school, he became a healer and kind of a workaholic. He loves his friends and family, but isn't good at surfacing from work. He's principled to the point of judgmental at times, and one of his friends nicknamed him 'Mr. Righteous' at school not exactly as a compliment.
Overall, though, he's a nice, friendly guy, and will be interested in learning non-magical medical techniques to go along with the ones he knows.