The fact that he has not had any more gout attacks, while great, doesn't mean that his diet is preventing more urate deposits from developing, so there is still potential for long-term harm. Early in the course of gout, it's common to have long periods between attacks. Even if your fiance insists that he wants to restrict his diet rather than take medication, he needs to have his blood checked regularly to be sure he is really accomplishing anything. I'm not sure why your fiance is avoiding salt and milk. There are no purines in salt.
Milk has substantial amounts of protein, but few cells, which is where purines are found.
There may be other good reasons to avoid salt or milk, but gout isn't one of them. Red wine was traditionally thought to precipitate gout. And it's true that alcohol can raise the uric acid level in the blood, so it should be avoided. This is one doctor who makes housecalls. People with lupus often find themselves in chronicpain, but there are ways to find relief.