My condolences on the loss of your mother
. It is hard to say what could have caused her death with so many medical things going on at the time. Did your family request an autopsy?
Please do not blame yourself, Lupus is sometimes called "The Great Pretender" because the symptoms can be similar to somany other illnesses and, sometimes, resemble just plain old fatigue. It is very hard to diagnose, even for Drs. who see several people with the disease throughout a career. How could you, when you aren't a Dr., and have not seen any other Lupus cases, possibly be expected to know that is what your mom had? The answer is : There is no way you could have known.
What is Chikungunya?