Welcome Kathie,
I too have been taking LDN or low dose naltrexone now for 34 months. I also take a low amount of PD meds, Sinemet and Mirapex. My neuro suggested I also take 1600 mg of coenzyme Q10 about 1.5 years ago. I began at 400 mg and she again told me to take more this Jan. I now take 800 mg of Q10 from Puritan's Pride. The LDN and Q10 are quite expensive but if you look at the per day cost, maybe not, assuming they do any good. I also take Magnesium and was taking turmercic (curcumin) but the neuro said to stop turmeric because it's toxic (I don't think it is). When I saw her last Jan, she said I had not progressed. It's hard too tell but I don't seem to be getting worse yet. Like your husband, I've been dx with PD for about 2.5 years now (it was MS before that). So I'm not sure what to expect, is the Sinemet masking the the PD while the disease is really progressing or is the LDN or Q10 stopping it in its tracks. I don't know.
It's nice to see another LDNer here. Ashley