How do I find out what awards and patches a deceased veteran was authorized to have?

As Next of Kin, you can submit a request to the National Archives for his military documents. You will need to supply the SSN of your grandfather to help better narrow the search down. The form and all of the instructions can be found on their website.

https://www.archives.gov/veterans

See if your county has a Veterans Service Officer or contact a local VFW Post, they might can help you with locating the DD-214.

PO2 Mike Shorey: This is a pretty good article on getting the replacement medals/ribbons, etc. Please note that there are requirements as to whom is considered next of kin in order to get the DD214, etc. I suggest you also talk to a Service Officer with the VFW, DAV, or American Legion who can obtain the various required documents to submit in order to get these items. One thing you will probably not be able to get are the personal unit patches. These were made specifically for certain units and were usually "unauthorized" (my husband's was the Warriors as he was 25th ID, 2/12th, Bravo Co. and he still has his personal "unauthorized" unit patch). To find out if your grandfather's unit had an "unauthorized" patch, you will need to get in contact with others who served in that unit with him. Best of luck to you.

https://themilitarywallet.com/replace-military-medals-awards-decorations/

My condolences for your Grandfather's loss. I had to get a shadow box made for my Hanai father and had to do a lot of leg work. First i went to his last unit and gathered what ever documents i could, mostly his DD-214 so that i knew what awards he had. get started with this websites;
https://www.loc.gov/vets/bib-factsheet.html
https://www.archives.gov/veterans/military-service-records
https://www.ebenefits.va.gov/ebenefits/homepage
https://soldierforlife.army.mil/Retirement
https://www.hrcapps.army.mil/Portal/default.aspx
If you are still looking for a really good shadow box, see this web site below;
https://www.shadowboxguru.com/
Good luck with your search, it was enlightening for me, learned a lot that he did not told us, don't give up, it will be a good one!

If you have his DD214 or a copy of it you can send to St Louis at the Personnel Center. Here is the info if you are still pursuing the awards:


http://www.archives.gov › personnel-records-center › awards-and-decorations
Military Awards and Decorations | National Archives
Jan 8, 2020 - How Do I Request Military Awards and Decorations? Important information for Next-of-Kin Cold War Recognition Certificate The National ...

Good luck with your quest into finding out about your Grandfather’s awards and decorations from his service in Vietnam,truly appreciate the honor shown to my Brother,I don’t know when and where he served but he always will be remembered by your actions,Thank you.

You can put in a Freedom of Information Act request. Just state everything you want to know. Google it for the form and address to sent it to. Remember when dealing with the Federal Government everything goes at a snails pace. Good luck PO2 Mike Shorey

If you have his flag from the funeral, then you should be able to get a copy of the DD-214 from the funeral home to start with.
With that it will make it easier for you to submit the paperwork to get a number of items from either the VA or other branches of government. Utilize the links at are available at the VA website and the one provided by CW4 G L Smith in his comment.

Most all counties have a VSO (Veterans Service Officer) they can assist you with getting your grandfather’s DD214 and his service records. Hope this helps you get your grandfather’s military history.