Yes but. In the 1950s, 60% of lupus patients died within five years. Now, more than 90% survive beyond five years. Many lupus patients have non-life threatening disease. Kidney or brain involvement portends a worse prognosis.
Yes. Lupus is an autoimmune disease, it means that the immune system recognize as "stranger" cells and tissues of the same body, reacting and producing inflammation and tissue destruction. It is very debilitating and, yes, you can die from it, due to organ damage.