yeah in real life there still isnt much to do. just make sure their head is resting on a soft surface, make sure nothings blocking the throat and wait it out. if it wont stop after 5 minutes then yeah call 911
tbh people in-game mostly did the right thing - they should've backed away a bit and forget off with the flashing avatars and perhaps quieten down to calm him further but otherwise there's not much they can do
if the person's prone to seizures i'd say being on vr is really dumb. its bad enough with games on a screen but this is a step even further