In the Shoe forum there are a great many threads and conversations about feet comfort so you may have some help there. This is one question the late @ECBG would have been so helpful with.
My DH loves the Copperfit socks but he went to a drugstore that sells them to be fit before he ordered them from Q. We also have a Good Feet Store that I'm trying to drag him to for a fitting to try special shoes, they specialize in orthopedics. He is just too stubborn to go and thinks that Skechers are all he needs but his feet and legs hurt so I'm trying to get him to a specialist. (been down the podiatrist route-he thinks the pain is in his leg so a podiatrist can't help and I cannot convince him otherwise.)
I have tried to find comfortable socks for years. The problem for me is that the top of the sock may have a band that cuts into my leg over time during the day. I've found that a sock labeled for a "diabetic" has a top that doesn't cut into my leg. Even a lot of compression socks have a "band" at the top. I suggest looking for socks labeled for a "diabetic". The issue for me is keeping the sock up and not binding.
Look for Diabetic socks. They sell them almost eve where. My friend gets them for her mom from Amazon but I've seen them at CVS and other places. Her mom isn't diabetic but she also has circulation problems too.
You will come up with the medical grade ones such as Medi and jobst and there are also the "generic" named ones of the particular site. They have differing strength.
If the person has circulation issues these are the ones that be of help to them.