Remember when Dwight Howard was drafted, skinny kid who could jump. A couple of years later, he looked like a combination of Hercules and Wilt.
Weight room.
If Ollie want Brimah and Facey to be post players, they need to put on twenty lbs of rock muscle. Their legs have to be stronger, their hands need to be stronger, their arms need to be stronger. Their games should improve dramatically if they add muscle. More than anything else they need to be on a muscle mass building program, at least, three days a week in the weight room plus a muscle building diet.
They need exercises specifically to build hand and forearm strength.