Fracture in folding frame - safe to ride?
Someone has to say live dangerously.  I would ride it.  Don't ride it hard but you should not ride a Dahon hard in the first place.  I looked at how the bike folds and unfolds and that is not a high strength connection in the first place.  

Bikes don't typically explode when they fail.  You get a bend and sometimes you don't even crash.

If it does die if you don't need a folder you can find decent used bikes for $400.