A method of deciding which pronoun to use the first part of the sentence and replacing the name (Todd) with each pronoun. From that you can see which pronoun makes more sense.
He is a very good student.
Him is a very good student.
His is a very good student.
The sentence that makes the most sense is:
He is a very good student
This means that "he" will go in the blank of this sentence
Todd is a very good student, isn't he?
Hope this helped!
~Just a girl in love with Shawn Mendes