Hello @beetlejeuse, Welcome to Connect. I know it must be difficult watching your father in pain and trying to help him find some relief. Thank you for being his health advocate in the search for relief from the pain of diabetic neuropathy.

@sash has posted about Loma Linda's INF treatment in another discussion here - https://connect.mayoclinic.org/discussion/nerve-treatment-anyone-tried/. I'm not sure @sash has tried the INF treatment but they may be able to share their thoughts with you.

Here are a few spinal cord stimulator discussions that might be helpful also.
-- Has anyone tried the HF10 Spinal Cord Stimulation Device? https://connect.mayoclinic.org/discussion/hf-10-spinal-cord-stimulation-device-relieves-back-and-leg-pain/
-- Comparison of Spinal Cord Stimulators from Boston Sci., Nevro: https://connect.mayoclinic.org/discussion/comparison-of-spinal-cord-stimulators-from-boston-sci-nevro/

If you want to learn more about neuropathy and different treatments available, here are a couple of really good informational sites:
-- Foundation for Peripheral Neuropathy: https://www.foundationforpn.org/
-- Neuropathy Commons: https://neuropathycommons.org/neuropathy/neuropathy-overview

It can really be confusing with all of the advertising and false claims. You might find these links helpful for evaluating information.

Quazar's guidance about avoiding scams and snake oil cures
-- https://connect.mayoclinic.org/discussion/how-to-avoid-quacks-and-snake-oil-treatments/
FDA's Health Fraud Page
-- https://www.fda.gov/ForConsumers/ProtectYourself/HealthFraud/ucm539101.htm
NIH's National Center for Complementary and Integrative Health (NCCIH) which offers guidance about integrative health and how to evaluate it.
-- https://nccih.nih.gov/health/decisions

Has your father's doctor or neurologist made any suggestions to help with his pain?