My brother is 38 an has been on a ventilator for 6 wks now, He is not responing any more when meds are lowered?

My brother is 38 an has been on a ventilator for 6 weeks now, He is not responding any more when medications are lowered. Is this a bad sign or could it just be that he has been on medication to long? His has small amount of pupil movement. Has been running fever for week or more, but not infection that can be found.