I am sorry to hear your son is having more pain again. I am handing you a Kleenex now and sending a hug

.
Having a discussion about getting the hardware out sounds reasonable. That could very well be part of the problem. There are some studies out there on hardware removal and in the majority of cases patients obtained pain relief and said they would do the removal surgery again. I am sure with a growing boy hardware presents all kinds of other challenges as well.
When you talk to the surgeon I would ask about the approach to potentially damaged nerves. If they find that a sensory or cutaneous nerve was damaged or is stuck in hardware or scar what will they do about it? Standard plastics nerve procedure is to crush and cauterize the end if a nerve cannot be salvaged. This prevents neuroma formation. If there is scar on a nerve will the ortho have the magnification loops and micro tools necessary to address that? Do they ever work with a plastic surgeon if they don't have the tools or skills? Places that do trauma or lower extremity restoration often do procedures with multiple disciplines. This may be overkill but I know you want the best possible outcome and preparation for whatever may be found that could be contributing. Hopefully it is just the dang metal implant!
Pre-op, 900 mg gabapentin is the new recommendation to reduce chance of chronic pain, post-op the antibiotic minocycline attenuated glia activation which reduces chance of CRPS. Regional anesthesia is helpful and if Pm or ortho recommends it they could give him a dab of ketamine during procedure to keep that pain memory from forming.
Of course there are risks, of course it is scarey and you want him as stable as possible before proceeding but there is also the chance that this could bring healing and pain relief. Either way we will be here with prayers and support.
Sending more hugs, Littlepaw