Both physical and cognitive rest are important in treating concussion (the part about cognitive rest surprised me!). So, perhaps half-days at school for a while?
The issue with CTE (Chronic Traumatic Encephalopathy) is a more difficult issue because a major contributing factor seems to be the accumulation of lesser blows. So, even if there’s a really good program to prevent, recognize, and manage concussions, it’s not going to help very much with this. Brain damage in many cases is probably caused by a combination of both. One study estimated that about 30% of NFL players will likely have real difficulties, often on the EQ (Emotional Quotient) side of the spectrum.
Let's assume, (1) the issue catches Ronnie's attention during a high period of his popularity, (2), he keeps the focus on high school and college athletics, and (3) he skillfully undersells the issue.