Reading about it today, apparently they DID give him an electrical charge defib (obscured by the people and the flag they put up.  Still very good that he was revived, but let's see what kind of diagnosis they get to.  In case of my son, they looked into:

1) Myocarditis as result of a recent viral illness (that was negative in his case, but the doctors would probably be professionally negligent if they didn't at least look at the vaccine in case that they do find mycarditis.  If they don't, the vaccine can pretty much be ruled out). I don't like the reflexive way the anti-vaxxers insert that into this, but the reality is that there IS some statistical links to increased myocarditis noted by several doctors now.  They will need to at least consider this when looking at all possible causes.  But again, if there is no myocarditis, then that potential route gets closed.

2) Congential condition such as CPVT (what my son has), Long QT, WWP (LaMarcus Aldridge), etc.  They could find one of these, but it wouldn't likely get confirmed until a treadmill stress test, and that would still be several days away, I would guess.

3) They will likely to a CAT scan of the heart, looking for minor deformities around the valves, a hole, any other structural issue (also not found in case of my son).  

Only when they've gotten through all this would a forward plan develop.  Still, the possibility that he might resume playing certainly exists.  If he has to get an implanted defibrillator, it will be a good 3-4 months before he could even begin resuming training.