Updated-though-not-final prediction on odds of eventual neurological outcomes:
Persistent severe damage: rounds to 0%, since currently he wouldn't even close to meet the criteria for severe brain damage.
Persistent moderate damage: 1%. It's arguable whether he was impaired enough even immediately on awakening to meet those criteria, if you were ignoring the communication difficulties that directly resulted from having a tube down his throat plus a pre-existing text-processing disability, and a degree of physical weakness (and need for strong painkillers) that is almost certainly mostly due to his physical injuries.
Persistent mild deficits: 47%.
It's a lot lower than before. 1 in 2, not 2 in 3. It's a good sign that Kalorm's mental status improved noticeably as he went from 'still very sedated' to 'only on painkillers, albeit a lot of them.' It's a good sign that he is showing any ability to follow incentives, if intermittently. He doesn't lose as many points as a neurotypical patient would for his instances of utterly ridiculous behavior, because apparently he's just like that as a person??? He can at least sometimes execute plans that require more than one step of inference, like "figuring out what elements he would have to draw to indicate his needs, and carrying out a frustrating ten-minute process to draw it." (There is, in fact, quite a lot of surprisingly complex implicit reasoning and theory-of-mind buried in that apparently-simple case of setting a communicative goal and doing goal-oriented planning for it; it's an area involving capabilities that humans have, that dolphins and apes have, but that even most relatively intelligent animals would fail.) He retains the ability to stick to a pre-decided plan even under unexpected duress, at least if you count "deciding it's a good idea not to tell anyone that he's having a hard time breathing", but that was a step toward achieving a later goal, at least in Kalorm's mind, and he did stay mostly calm for almost nine minutes, which is...demonstrating kind of a lot of willpower and emotional regulation, actually.
And they can check off some negatives. No seizures. No observed spasticity or abnormal reflexes, even mostly off sedation. If he has visual-field loss, it's subtle, and they haven't definitely noticed any agnosias; he recognizes Merrin and he's now interacted with various objects and not appeared confused about what they were. He has a surprising degree of retrograde amnesia about the events of the accident - a modest negative update - but, since waking, seems to be forming at least some long-term memories. His motor planning is at least intact enough to draw a picture that his brother could parse, even if only 4% of the prediction market contributors had any idea what it was (though to be fair, the PRIORS on what he meant were LOW.)
(There are other elements they can't clearly assess yet, and so can't rule out neurological impairment. His strength, coordination, and fine motor skills are terrible – but it's not clear if that's neurological in origin or just the inevitable result of two days in a deep medically-induced coma and currently being on a ton of painkillers, on top of a bad case of rhabdomyolysis. Overall, the markets are calling 60% odds that these resolve at the rate one would expect from a mostly-physical issue.)
But.
He clearly has pretty severe processing difficulties. Merrin and Khemeth are having to speak at, like, half of normal speed, and he still gets confused frequently if they include multiple pieces of information or complex clauses. His verbal processing is functioning at, like, the level of a 3-year-old, which indicates either an actual receptive language deficit, severe executive dysfunction and brainfog, or pretty serious sensory processing difficulties; most likely, some combination of the latter two. They have Kalorm's baseline psychometric results to refer to - well, from eleven years ago, he refused to be tested again after that - and this is not his baseline. Indications on his visual processing ability are even further below his baseline; a healthy Kalorm should find it trivial, and certainly not overwhelming, to scan a board of fifty simple images. A really unusually bad cognitive reaction to painkillers could explain most but not all of it. However, the Diagnostic markets are at 92% that at least 75% of the deficit is just...where Kalorm's current neurological function is at.
It's not the worst update. These are very common short-term symptoms even in the case studies of patients who recovered fully. Sensory processing deficits respond moderately well to occupational rehabilitation, and are areas where every indication is that Kalorm was functioning at a high level previously; a lot of the negative update is in just how big a drop there was, but it does also mean that Kalorm could permanently lose 2 SD in visual processing ability and this would still leave him at basically-population-average. (Not that this means he would be happy with the outcome. He would be able to tell the difference.)
Persistent executive dysfunction...doesn't respond well to rehab programs, and can be a very hard issue to treat, but at least it's likely to improve a lot once he's more fully awake. The degree of impairment hinted at right now is relatively common in severely ill patients even when nothing is wrong with their brain, just from sedation, pain, and sheer distractingness of the ICU environment.
The situation will almost certainly improve. In fact, in slightly more than half of worlds they expect to observe, three-months-from-now Kalorm will no longer experience subjective impairments, or exhibit any externally-obvious functional deficits; that he'll be back to normal, save probably a 0.3-0.5 SD drop in scores on a formal thinkoomph assessment, which they're unlikely to get data on given how Kalorm hasn't willingly taken a formal test since he was fourteen. Still, slightly less than half of possible futures are...varying degrees less happy than that.