Hello, my name is***** and I have over 20 years of experience as a veterinarian. Since Dr. G. isn't available I can step in and try to help. I am sorry to hear that Dakota isn't well and it sounds like he has multiple symptoms of liver disease.
His dark urine is likely related to increased spilling of bilirubin into his urine. Bilirubin is a pigment that the liver normally processes and if that doesn't happen it is excreted by the kidneys into the urine. Bilirubin can also increase when lots of red blood cells are being damaged, broken down and the body becomes overwhelmed with red blood cell pigments. Is Dakota anemic?
How was a gall bladder problem diagnosed? Was that assumed because he had high levels of bilirubin and alkaline phosphatase enzyme in his blood? High levels of bilirubin and/or alkaline phosphatase simply mean thick bile and sludging of bile, and difficulty with bile moving through the liver (cholestasis). If increased these values are increased we know we have problems with bile movement, but neither is definitively indicative of gall bladder disease.
Has he had a blood test called a bile acids test? That will tell us whether his liver is failing.
Bleeding from the nose can be related to an infection, either in the nose or a tooth root infection, a foreign body in the nose, ingesting an anticoagulant rodenticide (mouse poison), a tumor in the nose or clotting deficiencies. The liver is responsible for making clotting factors and in his case we know he has liver disease so it would make sense to assume that this is related to his liver disease.
Ideally a liver aspirate or biopsy should be done to diagnose his primary problem. We need a diagnosis to properly treat him. But if he has clotting abnormalities he would need a transfusion to supply him with clotting factors before that is done, and that too can be risky and is no guarantee he wouldn't still bleed profusely. In his case the risks may outweigh the benefits.
I do think that an abdominal ultrasound to evaluate his liver and other abdominal organs could be helpful.
What treatment has he been started on?
In dogs with nonspecific chronic liver disease I recommend a low protein diet (Hills L/d diet, Royal Canin Veterinary Hepatic Formula), antibiotics to control gut flora (which are always abnormal in an animal with chronic liver disease) as well as a medication called lactulose which absorbs some of the toxins produced because the liver isn't normal.
I also recommend a supplement that includes the active ingredient in milk thistle (silymarin) as well as s-adenosyl methionine. A product called Denamarin has both active ingredients and has been tested numerous times to make sure it is effective. These supplements help the liver heal and actually take over some of the liver's function so it is less stressed.
Because his clotting ability is affected he should also be taking vitamin K.
He may also benefit from supplementing vitamins B-12, E & A, all often deficient in dogs with liver disease.
Finally if he has signs of cholestasis, but does not have a blocked bile duct then a drug called Ursodiol can be used to help thin his bile and make passage through the liver easier.
The liver is an organ that can regenerate from an insult (toxin, infection, parasite damage), but not knowing the cause of his liver disease I cannot say whether that is possible for him. It is worth looking into his disease further diagnostically. I think he should have a bile acids test and an abdominal ultrasound.
If more testing isn't an option perhaps discussing my recommendations with his veterinarian to see if they make sense for Dakota would be a good idea.