There were actually THREE types of Bronze Star awards during WW2.The first is heroic, i.e., an award for a specific act of heroism on a specific date.The second type is meritorious, awarded for doing an exceptional job, usually over a period of time, in the combat zone.The third type is the 1947 award.In 1947 the government decided that every soldier who had earned a combat infantry badge was eligible to receive a Bronze Star.
I've never requested copies of medals, so I don't know if you'd get a CIB along with the medals.
It's possible but not necessary that one of the BS awards was for the action where he went MIA/KIA.Not all MIA/KIA's received BSs.
Bronze Star citations are held by the National Archives, Modern Military Branch, In College Park, MD. They are contained in a units General Orders, and are filed by unit, GO number, and year.(example: General Order #234, 1st Infantry Division, 1945). Numbering of GO's started over at the beginning of each year, so for every unit theres a GO #1 for 1944, GO #1 for 1945, etc.
Don't expect to find too much detail.BS citations are generally only 2-3 typed lines: name, rank, serial number, unit, location, and date