Benoit never need to "remember" matches. Old school types like him simply knew how to work the match on the fly. That is one of the more consistent things that appears to separate today and yesterday's wrestler; I have read in a few wrestling books how common it was to only be given the time you have for the match and possibly the finish, the rest was improvised. Today's wrestlers, from what I have heard, tend to practice the entire match or script the entire match before hand.
Anyway, another thing about her comment that is dumb is the if anything, Benoit is a wrestling machine. Even as his mind disappeared, all that seemingly remained was this pure wrestling machine. Benoit needed his brain to be a part of society, but his heart is what made him a wrestling legend.
Lastly...I still don't think he did it. I know there is apparently no evidence to support otherwise, but It still seems unbelievable that his mind degraded so severely, yet he was still perfectly functional and normal at work, yet randomly snapped on his own family? It just seems odd.