He should retire.
He has a magnificent record, and with a relentless workrate and a granite chin, managed to become a 2 weight world champion, unifying the light-welter division in the process.
There are no glories left for him to attain that are within his reach, and with the number of wars he has been involved in, his workrate and punch resistance can only diminish.
He has £30 million + ($50 million US ) in the bank, and the love of a nation. His after dinner speaking and stage tours (talking about his career, and an excellent line in stand up comedy), sell out in minutes, and he could walk into any comentating job he wants.
If he overstays his welcome in the ring, he will open himself up to criticism. He could not possibly have more love or loyalty from his fans, and will never have to buy his own drink in any pub in britain. We love him, he is ours- he doesnt need to do anymore for us, and he shouldnt take what is a great story, and let his pride turn it into a tragedy.