Serious chameleon questions please help?

so my boyfriend bought 3 Jackson chameleons from Reptmart.com about a month ago. 2 females and one male. he kept each Jackson chameleon separate, the male in a screen cage 16"x16"x30". and each female in separate 10 gallons tanks in the meantime while he ordered more screen cages. he gave the chameleons everything they needed, light, clean plants, food(which consists of fruitflies,crickets&worms that he powders with calcium bought from pet stores) and a lot of water. about 2-3weeks of having his chameleons, one of the females started to look sick, and weak. she wouldn't move and her eyes appeared sunken! my bf claimed that black liquid came out of her mouth. and then the next morning she died, with her tongue all out /: RIP<3 me and my bf were confused on what happened and read about Renal disease in chameleons, (which is an ilness from lack of water and dehydration) we guessed that was the problem and made sure he gave them extra water to prevent it again. after the death of the female chameleon, a week later (which is now) the male chameleon started having the same symptoms. weak ,eyes closed, not moving, black liquid coming from mouth, BUT the eyes seem normal. can anyone help me understand what is going on and what to do to prevent this? its so sad :( thank u very much