Strange symptoms; please help get us on the right track

I am trying to help figure out what direction to take for my boyfriend's really odd symptoms of illness. Here are some of the symptoms he has, which from what I've noticed occur after exposure to the heat - when exercising - or possibly when eating sugary foods. He's been having this pain since he was 14 years old, and he is 28 now.

-Extreme pain in his joints, similar to what I've read as sudden onset arthritis or Reiter's Syndrome symptoms. He gets the pain all over his body and sometimes the pain is accompanied with muscle spasms. The onsets are usually in the evening or at night. He says that he endures pain all the time but it sometimes becomes unbearable.

-Usually before onset his eyes are red.

-He experiences light sensitivity.

His older brother is a carrier of the HLA-B27 Gene and has Reiter's. However, my boyfriend never experienced any of the infections typical of what I've read that lead to Reiter's onset. *AND* the flare ups are more defined by exposure to extreme physical activity in the heat, or eating sugary foods. *I THINK*.

Neither one of us has medical insurance so this makes testing for any diseases/syndromes is out of the question. I am looking for possible holistic aides - and something to make the pain more bearable for him that isn't a strong OTC or prescription drug as we are both in favor of natural remedies.

Could diabetes cause these symptoms?