'Cryptogenic' cirrhosis means that a cause was not actually found on examination. However, the cirrhosis, which is essentially replacement of normal liver tissue with nodules of tissue separated by bands of fibrous tissue - destroys the normal function of the liver, and this in turn leads to hypoalbuminaemia due to poor protein sysnthesis by the liver. This, along with several other things, causes ascites and fluid retention - eg pulmonary and systemic oedema.
The renal failure is often an end-stage problem. Portal hypertension leads to ankle oedema and the petechial haemorrhages - small bleeds under the skin.
Acute hepatic failure often develops on top of the cirrhosis, and it is this that actually killed the patient; the liver just stopped working.
Gastric ulcer bleeding, in this particular case, was thought not to be clinically significant - i.e. it didn't contribute significantly to the patient's demise.