This has to be an incredibly rough time for you. Before I answered your post, I googled your disorder just to get an idea what you face under "normal" circumstances.

It does not surprise me that your friend is so important to you. Any impairment, be it physical or emotional often leaves the person who has it isolated, misunderstood and unsure about thier future. The fact that your disorder is not that common would make finding someone who truly understands you difficult. It must have felt like an enormous weight was lifted from your shoulders when you met your friend on the forum. Having her gravely ill is a fear I can only imagine.

You speak of people not understanding why you talk about your friend so much. As a whole, people tend to avoid conversations that they know little about or that have a negative aspect to them. (They may gossip, but that is different than talking about or listening to your worries about your friend). Because your friend is such a large part of your life, it only stands to reason that you would want to talk about her, whether she is well or as she is now in ICU. I think that in a lot of cases, people with physical or emotional disorders find that they live in a much smaller world than "normal" people. Often times we can't keep up, feel poorly or can't get around as easily as other people. I know for myself, before I go out, I have to make sure that I have my cane, medications, some sort of electrolyte fluid to drink and my phone in case I fall. That is just for a quick trip to the grocery store. Its much more complicated to get ready to go do something fun, and often, by the time I get everything together, I'm too tired or hurt too much to go at all.

Under normal circumstances, you would probably be able to visit your friend, talk to her and read to her, but as your relationship is through messaging and chatting, that opportunity is not open for you. I'm sure that adds stress on top of everything else. People that have been in a coma and have recovered sometimes say that they were able to hear during thier coma, but were unable to respond. Since you have called her in the past, if she is living with her parents, and they are willing, perhaps they will hold a phone to her ear while you talk to her for a bit. It might do both of you some good. At the worst, she won't hear you, but you have nothing to lose and perhaps it would give her some spiritual comfort.

I'm very sorry I don't have a better answer for you. I have only one friend, and we are very close. I worry about what will happen when she dies. (she is fifteen years my senior). I'd be beside myself if she were in the ICU in a coma.
Know that my prayers are with her and you as well. It sounds like she is something of a soulmate. Those are hard to find and the bond is extremely strong. I hope she is able to recover. Please let us know what happens.

Sam2