I have tried numerous supplements none have helped me. I take dicloflex SR which is hard on the tummy combined with paracetamol and take Lansoprazole to protect my tummy. Dicloflex does increase stroke risk. I think your partner needs to see his GP and hope they refer him to a pain clinic. There are loads of options for pain relief and people vary and works for one is not suitable for another.
My father does well on a ibuprofen and paracetamol. Once pain symptoms become permanent it best IME to never allow them to get out of hand I do this by trying to plan ahead when I am going to do things I know make me sorest and go up to my maximum dose before I overdo it. On supplements, I know a couple of people are doing much better on cannabis oil from Holland And Barrett I am going to give that a try at some point.