dont teach him how to deal with people making fun of his stutter, teach him how to deal with disrespect. if he was made fun of because he was short would you go to r/short? if he was made fun of because he wears glasses would you go to r/glasses? by teaching him it is wrong for ppl to make fun of his stutter you are teaching him he is different than everyone else and is the guy who needs special treatment. by teaching him how to deal with jerks, regardless of what aspect they hone in on, you are teaching him he is a valued human being who is deserving of respect, just like everyone else.