As I understand it, each plea deal IS different. The government doesn't have to offer a plea. The defendant doesn't have to accept. I'm sure the terms of the probation are also negotiable. As someone mentioned up thread, what benefit does it do to send the GF to prison?
People have gone to jail for much less than this. I think he should go to jail, if for nothing more than to be an example to the public that this type of negligence is not acceptable to society.
Never mind his other senses that could have clued him in to the window being open (hearing the work on the dock, the breeze from the open window, smell of the ocean, etc.)