Reactive Arthritus

My brother has recently been diagnosed with it, and it’s taking a real toll on him mentally. I don’t want to see it define him, and I’d be grateful for any advice on diet that he could use to reduce swelling, and if possible lessen the pain he is constantly in. He had it once before, 6 years ago, following a bout of amoebic dysentery. It lasted 6 months and went away. This time around, it has stuck with him for at least as long, and is showing no sign of going away. In fact, it has spread to his thumb, neck and shoulder. He has recently cut red meat out of his diet, and that seems to have helped (although he is even more depressed now) an fish seems good.

Has anyone else suffered from it, and does anyone have any advice on dealing with it?