> There were three hostages in his father’s apartment. He was also staying there, but the home belonged to his father.

Does it matter who owns the apartment? It seems likely based on this description he could be deemed as participating.

Like in normal domestic law, if someone is kidnapped, and the fbi raids the apartment where the kidnapped person is being held, i imagine everyone living in the apartment is going to jail. Who owns the apartment isn't really relavent.