Hi there -
The dose of Ativan your father was given the first time, and the duration of that therapy, is pretty much within the standard of care for ICU patients, who often develop a psychological problem known variously as "ICU syndrome", and some other less clear ones. It involves disorientation as to time, day vs. night, etc., and these patients also often become agitated. Ativan has been the usual drug of first choice, but of course doesn't always work well. Your father may be experiencing some withdrawal symptoms, but with proper weaning that should be minimal, and he is now getting a lower dose along with Haldol (which also can cause paradoxical problems of the sort it's intended to suppress). The duration (16 days) of Ativan therapy was not outside the norm, and while it's long enough to require weaning at that point, it just doesn't always work (I've seen this happen a good many times -- most of the patients came around and did well once out of ICU and their essential medical problems improved first).
It would seem to be a fairly "normal" kind of situation, given the unusual atmosphere of the ICU and its effect on a lot of people. Hopefully your father will begin to improve and can be moved back to a regular room and regain his orientation, which should also help with the agitation.
Best of luck to you and to him. I hope this is helpful to you.
John Kenyon, EMT, CCT
Non-invasive cardiology tech, Emergency and Critical Care technician, Critical Incident Stress Mgmt. specialist