I went through militarycac.com guide, made sure the following are correct:
-all root certs are on Keychain Access
-drivers are woking
-card reader can be identified by the Macbook
Things that I tried:
-disabled built-in Smart Card ability with the OS
-downloaded 3rd part Smart Card Enabler
-3 different browsers (firefox, safari, chrome)
-deleted root certs and re-applied them
His got a 2011 Macbook Pro (High Sierra) with Intel processor.
P.S. I own a Windows laptop, PC and a 2014 macbook. Never had so much issue trying to use smart cards.
I appreciate any help you guys can provide.