Good decision by BCCI to actually enforce the rule and ban him. Highly unlikely he'll ever be picked again in IPL even after ban ends. Very much possible that he might have been offered England's white ball captaincy that's why he opted out.
“An official communication has been sent to ECB and Brook about BCCI banning him for two years as per its policy which was informed to each player before they registered their name for IPL auction last year. It’s a policy set by the board and each player has to oblige to it,” a BCCI official confirmed to The Indian Express.