He wasn't on Okafor straight up so that obviously was not the strategy. They doubled Okafor every single time he touched the ball in the post. There are several reasons why they did that, but one of them is to keep Brimah from having to defend him on the block and almost certainly get in foul trouble. Can you think of a single possession where Brimah was left on an island guarding Okafor in the post?
Ollie's postgame quotes refute everything you're saying. He didn't want Brimah trying to take a charge (1st foul), hand checking 15 feet from the basket (2nd foul), or holding Okafor away from the ball (3rd foul). Brimah just isn't the most cerebral player right now.