Boss Feedback Appropriate?

BLUF: Manager is evasive and nonresponsive when asked for critical documents.  Is boss/peer feedback model appropriate?

This question actually from my sister who wanted to know "if that podcast I listened to had any advice on what to do when you need your boss to get something done but he just ignores your emails and in-person requests?"

Some background on the situation:

My sister works as an office admin for a small regional branch of a national corporation where she reports directly to the regional manager.  She also serves as the point of contact for all things finance.  Two months ago she asked her manager for tax and finance documents which are required to a) keep the corporate finance folks happy, b) keep vendors happy (by paying them), and c) keep the IRS happy.  She's past deadline on the internal requirements and vendor payments (including rent) are due "no later than right now."

The regional manager has a history of "rebelling" against corporate finance via inaction and dodging conflict (some of the documents needed for vendor payment require contacting vendors who are already upset about not being paid).

As far as communication frequency, she's been trying by email and in person about once per week.  When she's stepped up the frequency, he responds by taking an "I'm the boss and what I say goes, don't tell me what to do" attitude with the entire staff.  She provided the following example of an in-person communication:

"Hey, did you get a chance to get that [whatever it happens to be this time]?"
"No, I've been busy with [whatever]....."
"I'm going to need it soon. It's due [date]."
"Okay, I'll take care of it."

My tentative suggestion is to use the boss/peer feedback model but given the manager's volatility it would have to phrased very carefully.  My other suggestion was to look for a job where she doesn't have to clean up after her manager's alternation between passive-aggressive and plain aggressive behaviors!  Realistically, based on what I've bee told, this guy meets the standard of a bad boss.  (Yeah, she's listened to this podcast.)

Suggestions?