I guess Fortress thinks they can get a return on the assets, whatever they are. Could be a power play too, if you look at Theranos board there are a surprising amount of political players which could be advantageous for the SoftBank-owned Fortress.

Edit: looks like most of the original board members are gone post-scandal. But for reference here’s who was on it previously http://fortune.com/2015/10/15/theranos-board-leadership/