Regardless of the doc's credentials....
Dude has taken a lot of damage. I don't know about retirement, but a nice long break from fighting and sparring might be good.
Recent studies have actually shown that taking long breaks can reverse the effects of pugilistic dementia. But you need to do it before its too late.
Struve could take a year off and just train technique and grappling. Get in great shape. Get your technique perfect. Let your brain heal.
Come back and you'll be a better fighter.