Hola Emanuel
the verb ayudar is a transitive verb which takes the object direct pronouns la, lo, los, las. You may occasionally see it with "le", e.g. le ayudé, meaning "I helped him". In this case, when the pronoun is a singular masculine pronoun referring to "him", "le" is also accepted; but not if the pronoun is a singular feminine pronoun referring to "her". I that case you need "la".
I hope this clarified it.
Saludos
Inma
