Talk to General Practitioner on Sudden Liver Failure

My nephew felt pain in his lower half of right leg 7 days ago while he was in a village, Available doctor there gave him a pain killer injection (May be Dicloran) but pain did not came down, His parents took him to CMH for treatment, During treatment it was noticed that his entire skin color started to turn yellow, They referred him to Children hospital, Doctor there told that his liver has completely failed as bilirubin levels were very very high, Also elevated S. Creatinine level indicated that kidneys are also not functioning. After some time he was breathing difficultly. Doctor advised few test to identify the cause of this sudden failure but before we receive the reports the kid died. I want to know what could be the reason of thsi acute failure, As before 7 days he was perfectly alright and there was no signs of Jaundice or any other illness at all. Here I can attach only 5 attachments however I can provide further reports if some one can guide me regarding the possible cause for