Kohein whose vocal cords were damaged - can he duchen - v4 #9 by R' Aaron Cohen

A Kohein, attempting to smuggle a piece of bread for his sick mother, was caught by the Nazis and beaten mercilessly. His vocal cords were permanently damaged and his voice was barely audible. While suffering great emotional trauma, he turned to Rav Oshry with trepidation to ask: Is he still allowed to fulfill the Mitzva of Birkas Kohanim, despite the difficulty in making his voice heard to the Tzibbur?

Reference Material (pdf)