Stage 4 Lung Cancer - Bad Tarceva Reaction

Hello. My mother was diagnosed in December with stage 4 non-small cell lung cancer. She has never smoked a cigarette! The doctors started her on the Tarceva treatment pill because she had right gene mutation of the cancer. Unfortunately she had a horrible lung reaction to the Tarceva pill 2 days after starting it and was admitted to the ICU. Slowly but surely she has regained some strength and started on a chemotherapy treatment. Now her cancer has seemed to expanded into the lining of her stomach. She hardly eats anything. The only other options the doctor has presented to us is: Immunotherapy (which could irritate her lungs more) or a stronger chemo therapy (which she cannot handle with her condition of health). Has anyone else out there experienced a bad reaction to Tarceva or have any other suggestions of treatment options for stage 4 non-small cell lung cancer?