Interestingly after two and a bit years I finally feel that I have got to the position that I have now recovered as much as I am going to. My memory is never likely to be the same as it was and certain things are a wee bit slower than they were, but you also have to take in to consideration that you are getting older so things will naturally slow anyway.
I definitely feel CW helped me in my aid to mental recovery and in a way continues to do so. That's one of the reasons why I've kept practising. I use a piece of software called Morsecat which uses the Farnsworth method. You can character set your preferences, speed up, change intervals and create your own QSO's.
I can safely do 14 wpm at the moment with no mistakes but as my old teacher used to say, "push yourself, if you can do a certain number safely your finding it too easy!" So I'm trying 16 and seeing how I go, should prove interesting!
One of my pet hates is operators trying to prove they can send fast when obviously can't. A good operator can make the key sound like a musical instrument and if you listen even at speeds you are not used to, you'll start to pick out certain tunes. Things like RST or QTH TNX TEMP all have their individual tunes which you can easily pick out.
But there's nothing worse than hearing someone sending at speed with incorrect spacing and not sending correct timings on their tones.
But the biggest success to learning good CW is without doubt practise. Can't say it enough, practise practise practise! Even after you pass your morse exams keep it up or just do loads of QSO's. Some old boy said to me a long time ago, "try and do at least 5 QSO's a day to start with and I guarantee you'll soon become an accomplished operator!"