"The effect is that her involvement really increases our transaction time and costs. Also, our behavor makes vendors mad, causes missed deals, takes us off opportunity lists and others. "

Well, that issue(s) right there would cause me heartburn to no end. I would INSIST those losses come out of your Brother's share of the operation. I would refuse to subsidize, (lose money) because your Brother has married the North end of a southbound horse. Let him pay for what he's getting....