Authors Note: Because it is my headcanon that Martin gets along greatly with the Students at the shared house.
Martin didn't really mind that he lived in the attic of a house that was only inhabited by students. In fact, he actually liked it. He had lied a bit about the fact that he never spoke to one of them. It was true, that he didn't start conversations and kept his contact with the students as little as possible. But that didn't keep the youngsters adopting him as some kind of house-mascot. "The friendly ghost in the attic", that was how he had described his place in the house to Carolyn. What he hadn't said was that the students weren't afraid of ghosts. In fact, they kind of liked him – ...err them.
Seeing these young people moving into the house, studying, making friendships and working on relationships and leaving three years later wasn't too bad. Even if he wasn't their professor, their teacher, their brother or their parent, Martin couldn't help but feel a bit proud.
The students liked him because he was friendly and completely awkward, a personality treat they inherited themselves, maybe from the former student generation. Also, even though Martin didn't get paid for his job, he still had achieved his life-long dream; something all of them wanted but still had to manage in their lives.
It was a friendly coexistence, the attic-ghost airdot captain and the agricultural college students, enjoying a beer and talking about life. With a little more magic, one of them joked, they could assign to become a Hogwarts house.