There's a nazi in my basement!

Okay, so when i moved in here I was told about Dr C's father (X), how he was virtually incapacitated from old age, how he lives downstairs and that M is his carer. Since then I still havent seen the guy, but I hear him moving around down there, coughing, watching tv. And i'll admit i started to feel like a minor character in a film, but without the uplifting end bit where everyone cries - you know - that 90's Mel Gibson movie, where half his face is burnt off and he's a weird recluse until some kid finds him and teaches him to live life again (soppy shite really).

Then the other day, Mad M says to me, "did you know X was in Hitler's army?"
*Hello? What? Choke on some wine! Light a cigarette!*
Apparently, not only did this guy fight for Germany in WW2, but was a ranked soldier in the SS!!!!!! He came to England after the war and settled here.

Mad M says he claims to have been shocked when he learnt what the Nazis were up to. I call "bullshit" to this statement. Maybe I would have believed him if he was just a normal citizen there at the time, but the SS were Hitler's private army, right? How's my historical accuracy on this point?

I havent even met the man, but it freaks me out to know that he's down there. Am I being hysterical? Let me know what you think!