He probably saw him as a Good Samaritan or one of those desperate ones.
Referring to himself as her guardian, the doctor handed him some bottle of pills and instructed him never to leave her alone in the house for her safety. It was ridiculous request seeing as she wouldn't even have a normal conversation with him.
She looked so peaceful on the bed. It looked like she was in a deep sleep and Nathan wanted to be her charming prince. To kiss her senseless so that she would wake up. As tempting as that was, he knew she wouldn't appreciate seeing his lips on hers. He settled to holding her hands anyway.
As he held her hands, he suddenly felt her slipping away. He didn't know why but it was like she would never come back. He didn't know if he should call the doctors because Antonia's hands were starting to feel cold. It was eerie.
He considered calling the doctor back in but he couldn't seeing as it was just him feeling it. It could be that he was being paranoid.