Oh, dear. I am so sorry Cali is sick again.
Lady had HGE three times in four months last year.
HGE can be caused by a bacteria (Clostridium). Was Cali on antibiotics the last time?
Pets Health
I agree with Luvmysissy. Probiotics and colostrum to boost the immune system may really help.
I use Animal Essentials Plant Enzymes & Probiotics and Transfer Factor:
Amazon.com: Animal Essentials Plant Enzymes and... Transfer Factors in Veterinary Medicine: Canine, Feline, Equine and Livestocks
What do you feed Cali? I switched Lady to a homecooked diet and added probiotics after her last HGE episode because she got diarrhea again just a few weeks after I started her back on her commercial food just like Cali. That was right after Labor Day and, knock wood, she's been fine ever since.