I just wanted to point out a couple of things (first with the caveat that I am not Steve Jobs's physician and I have no personal knowledge of the case; however, I am an academic physician at a major medical center)
1) We simply cannot assume that Steve Jobs's diagnosis was (or is) completely known. The list of things that can cause someone to lose weight after a Whipple procedure is very long, and the testing for some of the possibilities is not always reliable. Clearly he has been losing weight for months, but his physicians may very well have been searching for the entire time before coming up with a diagnosis and treatment plan. Among the many possibilities is a recurrence of cancer, though other causes are in fact more likely.
2) If the diagnosis is not known, then prognosis is almost impossible to predict in a case like this. We still don't know enough to guess whether he is in fact dying, or going to make a complete recovery (or anywhere in between).
Therefore, allegations of "painting an unrealistic picture" or "major communication breakdown" are speculative at best. Either is possible, but so is the possibility that Steve is telling the truth and attempting to minimize the effect of his health issues (which are personal) on the company and shareholders.
3) Steve is clearly a brilliant man in his own field. I have treated many brilliant men (and women) and can confidently say that being brilliant does not necessarily translate into being medically knowledgeable nor savvy. Any patient presented with a confusing diagnostic picture must be confident in the final diagnosis and likely will seek multiple opinions (and appropriately so...) before deciding on treatment options.
I recommend that we take him at his word, and wish him the best.
For myself, all I can do is wait. Overall, Apple should do well regardless of Steve Job's future involvement, in large part due to his past involvement.