D..
I'm so sorry. I know this is scary for all of you.
I remembered that you asked about your MIL forgetting your daughter's birthday until later in the evening and your daughter being upset about it. Was this forgetfulness last month an isolated incident? Or have you seen some changes IN TIME with your MIL's behavior or memory?
The passing out is not part of Alzheimers/dementia. If she was not uncooperative before the passing out, then this is something else. When they scan her brain, they may see that she has had a stroke. I don't know what to tell you about metal in the brain.
As a matter of course, hospitals talk to people about DNR's. Before going into surgery, they always do, even for young people. Your FIL might not know that and he might think the hospital thinks she is going to die. He needs someone to be with him as an advocate to ask questions. Not pressing an issue is not helping him. He needs to be informed so that he can figure out with the doctors what the next course of action should be. Ask for a hospital social worker, Gerri. It's their job to come be with you all and help you get answers.
I hope your daughter is okay. You can talk to the social worker about how to help her through this, too. According to how severe the diagnosis is, you may want help preparing your daughter for bad news.