In this sentence, the pronoun "he" is substituting for the noun "Cassidy".
In this sentence, the pronoun "he" is substituting for the noun "Jim".
In order to determine which noun the pronoun "he" is substituting for in the sentence, we need to look for a noun that was mentioned previously in the sentence. In this case, the only possible noun preceding the pronoun is "Jim." Therefore, the pronoun "he" is substituting for the noun "Jim."