Consider the following German sentences, both of which my German teacher says are correct.
Elmar (13) ist nicht gut in Englisch.
A: Der Vater will dem Jungen helfen.
B: Der Vater will den Jungen schlagen.
Why is it such that 'Jungen' is in dative in the first sentence and accusative in the second sentence, when it in both cases is the father who wants to perform an action toward the boy. My teacher said that it is because 'helfen' is intransitive and 'schlagen' is transitive. However, I don't see why this should affect the case. Also, why is 'helfen' intransitive? Can't I just say "Ich helfe die Spinne." in response to someone who asks me what I'm doing? (Thus supplying an object).