Helwan is indeed the true necropolis of Memphis since the Protodynastic and almost all the tombs date from Dynasty 0 (Horus Ka) to the Third Dynasty.
It was here that Saad uncovered two ivory Djed pillars as grave goods.
This is not taken from some 'Antiquarian Handbook', but it is historical fact.
Given that you acknowledge the decoding of symbolism to be open to interpretation, we will just have to disagree on the significance of the Djed pillars being consigned to a grave from the first dynasty. For me, they are associated with the life eternal and for later dynasties of Egyptians when the Djed became unambiguously Osirian, it meant the same for them, too.
What does it mean for you? What prompts you to consider it a "healing device"? I would genuinely like to hear how you have arrived at such a conclusion.