I am currently reading "Unjust Enrichment" by Linda Goetz Holmes, which is about the "white" prisoners of war that the Jap corporations used during the war. I recommend it. And I commend your grandfather, for being able to live through it. If he's still among us, give him my best regards.
He not only had to survive years of "hell" in those mines but first had to survive the "hell ships" that transported him and his fellow POW's from the Phillipines to Japan.
I'm sorry if I don't have as much "sensitivity" for the "survivors" of the internment camps here in the U.S.. Sure, it would have been better - perhaps - if we had not done it, but they've been compensated. Now, it would be much better if they either supported reparations for your grandfather and the others who were horribly abused by the Jap corporations, or just shut up.