If the dog eats lets say a piece of chocolate then hes fine probably will just get sick that's what happened to my dog but too much chocolate the dogs body wont be able to digest and that's how they end up dying .
Depends on how much you give them at a time if they eat a hole bunch of chocolate in 3-4 weeks no they will not die because it will eventually digest but if you gave your dog a hole bunch of chocalate in a day you better be sayin your prayers.
If he consumes too much of it then yes. There is a chemical in chocolate that if too much is consumed then it can make the heart stop completely. So to make it clear Do NOT feed your dog/cat chocolate!