I have found that applying the correct pronouns and possessives to a sentence causes great problems to students. Either because they confuse them, eg: him and his, their, theirs and them etc.... or simply because they cannot relate to the speaker of the original sentence.
To help them "see" I tell them that all first persons in a quoted sentences relate to the SPEAKER, and all second persons relate to the "LISTENER" hence, the first thing I tell them to do when they are beginners is to underline all 1st and 2nd persons and draw arrows from those words pointing to the speakers and/or listeners... then.... substitute them being aware constantly of the gender.
Tom said to Mary, "I have your money in my coat pocket."
he her his