Not sure what kind of info you are seeking, Debbie.
If you mean info about his service, you should be able to get his personnel record through the NPRC in St. Louis. (They had a disastrous fire in 1973. However, they indicate that Navy Dept personnel records - which includes Marine Corps - were not affected.) Info on that resource can be found at this web page: http://www.archives.gov/st-louis/military-personnel/index.htmlhttp://www.archives.gov/st-louis/military-personnel/index.html
You might also try the Raider Association. My father belongs to the 1st Marine Division assn. They have some info about him, including his unit. If the Raider Assn has similar info on your grandad, and they are at liberty to share it with you, they might also be able to help. Their web address is: http://www.usmarineraiders.org/index2.htmlhttp://www.usmarineraiders.org/index2.html