
I found Cortaflex helpful too. My girl I just lost who had HD was on Metacam plus Yumove plus one Tramadol, which worked well for her. Previously, she was on PLT (prednoleucotropin) instead of Metacam which worked well too. PLT has 1mg of prednisolone in each tab, and so some vets don't like prescribing it long term, but my girl was on it over 3 years with no problems. I only changed her to give her a break, though my vet assured me she didn't need it, as the amount of steroid was so small. At a certain age and condition it is a trade off.
Please get him back on meds soon, I am not surprised he is struggling to stand and move, now he has nothing to help he may be in a great deal of pain. I believe Loxicom is the same as Metacam by another name, and you will need to have him on this continuously for HD, and it can take a little while for the benefits to show. Any of the other supplements would be in addition to this basic anti inflammatory and pain relief medication. The vet can also prescribe Tramadol in addition for pain relief, it helps some dogs. With very bad HD, at his age I think you will need a combination of things to give him the best quality of life. JMO, having been there a couple of times.
Also bear in mind that you can get a private prescription from your vet. I used to get 180ml of Metacam from Hyperdrug for about £19....a huge saving when the vets charge about £60 for 100ml.