The worst thing I've ever been told by a nonprofit client:
Our president has a very strong and unique voice. It's critical that all materials you write for us adhere to that voice.
Every time I've heard this, the result has been the same: The boss' unique writing voice doesn't adjust to effective fundraising writing. In fact, it pretty much outlaws it.
The unique voices of boss after boss are surprisingly similar to each other: formal, complex, hard to read, self-focused, padded out with abstractions.
So fundraising limps along weakly, with tepid response to every campaign.
The odd thing about "voice" in writing is that most people don't recognize it at all. It's something they heard about in some English course a long time ago, not a practical reality in their own writing.
You have to be an experienced writer to grasp the idea of voice. Some of those "unique voice" bosses get that much. But they're unaware of an even more important feature of voice:
Expert writers understand that voice adjusts to its audience.
The very purpose of "voice" is to accomplish a goal.
If you find yourself struggling with a "my unique voice" boss, you have my sympathy. If the boss is a reasonable and insightful person, you may be able to have a fruitful discussion about the issue. You can use the many books and blog posts about effective fundraising writing to make the point.
Some bosses will listen to you. Some won't.
If you're stuck with the second kind, I suggest you start looking for a different job. There are some amazing leaders out there who will let you do your job and thank you for not wrongly applying their voice to the fundraising!