75 yr old mom still in ICU - over a monthssince surgery

My mom had open heart double by pass surgery sept. 9 along with a valve replacement. She is abou t50 lb overweight and is a diabetic. She has had an extremely slow recovery, spending the majority of the past month in ICU. She had some seizures and was hooked up to an EEG machine - had to have a breathing and feeding tube. I read a few of the doctor reports saying her brain activity has slowed from 7.5 hz to 4.5 - what does this mean? They now removed the respirator, but she does not recognize her family and can barely speak. The doctors and nurses refuse to give us a prognosis. What can be done?

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Hi Colleen,
               Oh my, I'm sorry to hear about your problems, and I know it must be scary. The Doctors won't give a prognosis when they don't know something. The brain is still a huge mystery with many respects and everyone recovers to different levels and at different rates.
The frequencies you mention are meaningless really, because you need to know the location and amplitude to make any sense of it. There are some parts of the brain for example you would expect a lower frequency, but in other parts of the brain could indicate coma. So, just the frequencies alone mean nothing. USUALLY frequencies of 8hz and above are related to an adult awake and alert, but lower numbers can just mean in meditation, totally relaxed, sedated, asleep etc. It depends on the area of the brain which was observed.
The different bands of frequencies are Alpha, Beta, Theta, Delta.
If a Doctor tells you something that you don't understand, my advice is to pester them until they explain it properly, and don't let them leave you until they have. Even if they have to draw simple diagrams, never feel embarrassed to ask and ask and ask.