Well, who is to say "who" exactly is wrong?

Is this foot doctor going to say--- it is my fault, and Alan's problem is a long term infection I am not being aggressive enough with? (since this appeared next to the original lesion )

Or is he going to blame the orthotic company?

Given the odds I'd say most doctors blame someone ELSE.

So getting irate at this point may be counter productive.
Do you have proof the orthotic is improperly made? not at this point.

Has Alan's foot changed any? You don't know that either.
Has this foot doctor ever cultured the pus to see what organism(s) are present? Or does he just give you an antibiotic off the top of his head?
A chronic lesion of any sort is typically cultured to see what exactly is going on...in this day especially with mrsa around!

After reading this long story for many months, I still think you need another doctor's opinion. It is possible this is a deep issue, long standing needing more aggressive treatment.

Perhaps a consult from a wound specialist? Something else of quality in any event.