All BS aside about skill, etc., McNamara needs to take care of his brain. Concussions are a nasty, nasty animal and affect everyone differently. There are people who get one concussion and have problems for the rest of their lives. There are people who have multiple and don't have any noticeable effects. The problem is you have no idea until you get one, and then it's too late. There's no effective treatment for TBIs that get you back to normal once the symptoms start. None...
There are things that can help slow it possibly, but there's no repairing whatsoever.
Favre, Kosar, Jim McMahon and myriad others have millions and millions of dollars collectively, but if you also have dementia to go along with it, none of that money means a thing. Jim McMahon can't leave the house without his wife or someone with him because he's gone out before and all of a sudden not known where he is, what he's doing there, or find his way back home. Favre is on record saying he has about 20% short term memory now and can't remember ever going to any of his daughter's soccer games of which there were dozens.
If CM takes another shot two weeks after bouncing his head off a carpeted concrete floor he could be the same way. Tua's going to be in a wheelchair at 50 drinking pureed carrots for lunch. But at least he'll be able to afford the nicest nursing home in the country I guess.