Seems a little gangster when you know germans often use the present to express the future!
"They are having an accident." is also accepted as correct. Which makes more sense if it is actually happening in front of us now. We would expect more information with the other version, for example: They have an accident every other year! How do they have such bad luck? or "They have an accident when they are not paying attention to the road. So we don't want anyone to text while driving."
I don't know about the German, but in English "They had an accident" is much more likely to be used than "They have an accident." As soon as the accident occurs, it is past. Is there even a natural usage for the present tense of it (in English or in German)?
had an accident" is more common than "they
have an accident." Would "they
are having an accident" as the present-tense translation sound better to you? It would still be uncommon--usually by the time you could comment on an accident, it's over.
Perhaps in the context of a toddler . . . .
Fact is, at the time when I got this sentence, we had not yet been taught how to use the past tense in German -- which, imo, would justify DL's use of the present tense in this sentence.
But its not in past tense. 'They are having an accident' is correct for this sentence. It would just be really rarely used.