Monitoring of patient after by pass surgery

My father underwent a by pass operation and was in ICU that night and the next day. The following day, at he was left in a privte room by himself with no machine monitoring, only the routine nurses checks.While he was asleep, he went into VF and never recovered. I am trying to seek advice on what is the protocols around patient monitoring after by pass? The doctors are only stating that my fathers outputs were showing that he was progressing and that budgetary constraints would not allow for machine monitoring.  I am about to go into mediation with the doctors who cared for my father. COuld you please advice me on any questions which I should be asking. I dont want to sound numb and come away with a lot of medical terminology that I dont understand. Your help with this matter would be appreicated greatly.