Did he document the brake problems he had 'shortly after delivery' as this could be crucial.
Had the 24 month warranty expired? Even if it had, he still may be able to get the MoCo to fix the brakes if the early documentation is in place.
Introducing aftermarket products now would only seem to muddy the water to me, and at a hefty price, too. Harley's brake's aren't inherently bad news, but that dealership could have overlooked something it shouldn't have. If your buddy has his bike repaired by this shop again I'd insist on a better mechanic working on my brake system this time. If they don't have a better mechanic maybe it's time to take the bike to another shop.
Phu Cat