質問: For more context, see the full text here: Taken from line 3: すると、一人の男が「そんな物、怖がって**どうするんだ**。...」といばった。 On jisho, どうする translates into "what to do about it" I feel rather unsure about the implementation of this meaning here. I'd translate the sentence like this: "Hereupon, one of the men bragged: "Such things, being afraid what to do about it?..." I think this phrase goes in the direction of "Such things, why bother with being afraid?" or "such things, what do you do about feeling afraid". The latter would imply a question about what they do to cope with it. I would say that the first of the two interpretations is probably more fitting here, but as I said, I don't really know what to do with this どうする here.
回答: The guy is basically bragging that he is not scared of that "thing", and in a way mock everyone who is scared. The どうする might not be easy to understand. It technically means, > > "what you gonna do about it", > > > but the meaning is more something like, > > "how can you keep on going(living your life etc...) if you can't handle this". > > "What are you gonna do if you can't even handle that". > > "If you can't manage that much, there is nothing you can do(you are doomed to failure/mediocrity)" > > > Another easy way to understand might be to see it like this. > > Oh no what shall we do! > > >