Searching for relatives "Hongo"

I'm taking the step to find my grandfather "Ichiro Hongo" he was married to my grandmother after the war on an island called Angaur in Palau. They moved, my father "Jesse" his younger brother "Denyo" and my grandmother Eiko to Tokyo Japan but she had a culture shock and moved back to Palau with my father and brother. My siblings and I have been searching for him all our lives but to no avail. I know he was a mechanic of sorts working on the ships and equipment and an only child to his parents.A darker shade compared to the other fair Japanese expatriates from Japan who lived in Palau. IF anyone can direct me on how to locate him or any living relatives please let me know. I have tried many times but keep getting lost in the process.Thank You for taking the time to read my request.