I think it's hard to answer that. Some people end up with what amounts to dementia (Stabler, McMahon), others have turned to suicide, a few, like Hernandez, become violent. I would think the CTE is accentuating what's already part of that person's psyche, but like you, I'm no neuroscientist. I do believe MI does have a science career bg though, and always welcome his thoughts.
IIRC, Hernandez autopsy showed the worst CTE ever seen at that age. Stage 3, nearly stage 4. That's what's seen in players in their 60s and 70s after long, rough careers.
As to the Patriots, I think they will be better off without him, that team is already stacked. Like 15-1, another Super Bowl stacked. That's my thought anyway.