I have to say, I am surprised and a little worried by this.
That last concussion was little more than a rap, and left him punch drunk, staggering, and collapsing.
The only logical inference is that the multiple concussion have had some kind of cumulative effect. Perhaps damage, or perhaps just weakening of whatever hold the brain I place.
Do I know more about brains than his doctors? Presumably not.
However we should realise that this would not have been a clear-cut decision. The Doctors will not have said "Its safe for you to continue playing." They will have outlined the risks, and collectively they have decided the risks are acceptable. That is where I disagree.
Most athletes retire with niggling injuries. Bad backs, dodgy knees, etc. Its the price they are prepared to pay. No doctor ever said to them that it was "safe" to play another year.
The difference is that a dodgy knee won't stop you being a father or husband, or from having a white-collar career, or give you parkinsons, or put you in a early grave.
I don't want to read in 10 years time that Matty and his family are destitute because they've blown all their money on medical bills, he can't hold a job, and his wife has quit work to take care of him.
3 Championships is enough Matty. Time to give it a rest and enjoy yourself.