Because enough time has passed you can request his entire OMPF (service file) From NPRC in St. Louis. You don't have to be next of kin to get it at this point if he was discharged in 1945-1946. That file will contain more information than what's on the discharge.

Once you have it, sort it into date order and do not toss the pages that appear to be duplicates. They are not. The Navy would create a document and then it would go to other offices and get a stamp or date or something added. So they are not duplicates but do contain additional information.

Put the file into chronological order because it won't come that way then create a timeline of service so you can clearly see dates, ships/stations, and details. Once you have this information, Then there will be deck logs at NARA College Park and other records like unit histories, action reports, photos, etc. Some may also be on Ancestry and Fold3 like Navy Muster Rolls or WWII War Diaries.

If you want to see some examples of Navy service files, you can visit my website WWII Research and Writing Center. Go to Research Resources and WWII Record Examples. You'll find some there. My grandpa served in the USNR Armed Guard as well. There will be separate Armed Guard deck logs at NARA.