Grass was drafted into the Waffen SS as a 17 year old recruit at the end of the war. his choice was to join or be a dead man. Incidentally, the Waffen SS had nothing to do with concentration camps. That was the responsibility of the political branch of the SS.
U.S., allies conduct 1 air strike in Syria and 11 in Iraq against ISIS militants (Reuters)
from the article: Interior Minister declares Gunter Grass persona non grata in Israel