...Unless he switches to Mobil 1 synthetic. It will reduce friction and you won't have to change your oil so often.
But, at 120k miles, I have personally seen Mobil 1 cause older engines to start leaking oil.
et conversum est retrorsum iudicium et iustitia longe stetit quia corruit in platea veritas et aequitas non potuit ingredi
"Liberty without morality is simply slavery to self." Me