I have been to that camp and it gives me chills just thinking about it today. It is amazing how people survived, I also visited the camps in Thailand and Singapore. The soldiers suffered almost identical to Bataan's soldiers, it's sickening that people can be so cruel to another human beings.
The women in the Philippines and I'm sure in other Asian countries were raped repeatedly by the Jap soldiers, my own grandmother had to get married as early as 16 to avoid getting raped by the Japs, (they preferred virgins).
Thanks to your grandfather and the very braved soldiers who fought for freedom. The whole of Asia would be speaking Japanese today if it weren't for their bravery and determination.