What does their diet consist of?
There are a number of things that can cause jaundice in tortoises ibut being its both of your guys that have the problem I would think it may be a diet high in proteins or fats, over supplementation of fat soluble vitamins. It is treatable and here is what can be done:
i) Maintaining the tortoise at a steady high environmental temperature to stimulate both metabolism and immune systems.
ii) The use of antibiotics
iii) Rehydration- it is important to maintain a suitable level of hydration and even to promote drinking/fluids to facilitate renal function.
iv) The use of small amounts of very low protein green foods by tube feeding often started but is especially important in the cahexic animal.
v) Oral administration of methionine and/or the use of anabolic steroids may be indicated. Total liver failure is obviously incurable, but many cases respond to this therapy. Further investigation may involve blood samples, faecal samples, x-rays and even liver biopsy but may not affect the outcome even if getting closer to a diagnosis.