I'll clear up a few things:
Two things are of CRITICAL importance in an event such as this (assuming this is cardiac arrest):
1. Time from collapse to CPR is crucial. Immediate CPR is ideal and this appears to be delayed beyond what should be expected at such an event. However, the timeframe we're dealing with is not such that you immediately expect a bad outcome. He is young and youth can do A LOT for you.
2. Equally, if not MORE important is: time from collapse to delivering a shock for a shockable rhythm (not all heart rhythms in cardiac arrest are shockable). The fact that he appears to have received a shock is actually quite good news. Moreover, the fact that he was not receiving CPR en route to the hospital means they restored the proper electrical rhythm. If they had not, he would be dead.
The fact that his echocardiogram was "normal" is not entirely reassuring at this point. If he truly had a period of "not feeling well" leading up to the race, he may well have had viral myocarditis (virus-induced inflammation of the heart) predisposing him to dangerous electrical arrhythmias. Alternatively, he could still have hypertrophic cardiomyopathy as they do not all present with the classically thickened heart. A more detailed echo following his hopeful recovery with provocative testing and a cardiac MRI will help to sort out this question as well as the myocarditis possibility. He will need a detailed look at his EKG and likely genetic testing to look for abnormal conditions predisposing to arrhythmias such as long/short QT syndrome, CPVT, brugada, etc. These will take a well-trained electrophysiologist and a genetics team to sort out. Lastly, the decision as to whether to pursue a heart catheterization will be up to the medical team both to assess for traditional heart artery blockages (less likely in a healthy young man despite what you may read in the NY times or elsewhere), but also to assess for abnormal anatomy of those same heart arteries which can sometimes go undiagnosed for your whole life until one day you have an arrest.
Several AED's should be positioned around the arena (not just one) and medical personnel should not be clustered in one corner. These events are thankfully rare, but when they do occur, they are devastating.
A period of hypothermia will likely be induced with gradual rewarming and neurologic testing to follow. The timeframe for this is usually over the course of the next 24-72 hours. Initial head CT is good news, but this is only going to show information in the worst of scenarios and is subject to change over the course of the next several days. He will likely be in a coma and possibly paralyzed. So, news of recovery (neurologic) will come after some time unless his recovery is speedy.
I agree with the sentiments shared here. Everyone who is willing should learn CPR. The difference between my CPR as a cardiologist and yours if you're properly trained is essentially nothing. My skills only come into play once medicines and procedures are involved and thus, I believe most people underestimate their ability to save a life.