How do you set a Vietnam era ASU?

The Green Service Uniform is relatively unchanged since the 1958 inception until it was phased out in 2013/14. It changed shade a number of times. The current 670-1 will be close enough. Getting a back copy of 670-1 and I believe 670-2 will be tough. The fundamentals are the same.

My concern would be having it cleaned without it disintegrating.

Do you have the DD214 to set it up? You'll have to get OD backed overseas service bars and service stripes. Unit awards will be the most difficult to piece together. The color patches are still readily available either from insignia suppliers or surplus stores like Eagles Of War in Clarksville TN.

The VFW helped a friend of mine do his Grandfathers !

SGT (Join to see) What a Beautiful Challenge to Take On!

SGT (Join to see) Does your friend have access to his grandfathers medals/ribbons, awards, rank, etc.? If he has his grandfathers DD-214, that will list the medals earned.

https://www.google.com/search?q=military+asu+uniform+setup&tbm=isch&source=hp&sa=X&ved=2ahUKEwjyo-Swk9rgAhUOvp4KHTmSB_cQsAR6BAgFEAE&biw=1920&bih=931

Once you know what awards are on the DD214, use one of the online sites to makes it easier to determine the proper order for the awards (and difference between unit awards and personal awards). I've included a link to Rackbuilder, but there are others.
They also have shadow box builders.
You may find a used version of the uniform at a military surplus store, local or online.
Great project.
https://www.ezrackbuilder.com/rack-builder/home

Very noble deed. I too would like to recreate my father's Navy uniform if anyone can help.

PFC (Anonymous): That looks rather dusty and in need of a pressing. Before you take that to a dry cleaner, make sure they do proper restoration of older uniforms, wedding dresses, etc. Otherwise, you are going to end up with one severely screwed up uniform. You can always ask the dry cleaner if they do restoration dry cleaning of period pieces or you can ask around at local places, like an historical society, historical museum, etc. to get good information on who to use to dry clean it.
After it is fully restored, make sure that it is not kept in a plastic bag (from the dry cleaner or suit bag used for traveling), plastic anything. This disintegrates the fabric, including the ribbons. It's better to put it in a black shadow box or a wedding dress preservation box. Ask your local dry cleaner for the wedding dress/wedding tuxedo preservation box. Or you can get a suit bag that is made from cloth, preferably cotton or cotton blend.
My husband still has his old uniform, although he couldn't fit into after he was home for 3 months (long story short, he lost 35-40 pounds in Nam humping). When we got married I transferred it to a cloth suit bag and kept it in the closet away from dust, sunlight, etc. It's still in beautiful condition. Best of luck to you and what a wonderful surprise.