What do you should you do during a Lyme's disease flare up?

My boyfriend recently found out that he has Lyme's disease that went untreated for several years. His weight has gone down recently so his immune system is low and now is having a very bad flare up that is mimicking the flu (he had previously suffered from Bell's palsy as a side effect of the Lyme's). What can he do besides what a Dr could prescribe?