>>Ask him if he plays for the English or the Germans.
"... I don't know what you're talking about. Aren't they the 'eliminated races' from World War Five?"
>>Join forces against your oppressors. Mate. Spawn a whole fucking army of super mutants.
"I don't even know if I have any oppressors... or if I already killed them all..."
>>"Hello.. I'm not here to hurt you or anything. Are you okay? What happened here?"
"I... I woke up on a room nearby and saw those dead bodies lying around... t-t-then I saw my hands... They were so bloody, but without wounds...
... I might've killed those humans with my hands..."
Judging from his disgusted face, he does not seem to be comfortable talking about it.
>>Ask him if he wants to join your party.
"... But what if I kill you without knowing? I'm so scared..."
It appears that Danny is a bit reluctant to join you just yet.