What Causes Walking Difficulty While On Fentanyl And Midazolam?

A 92 year old man was given fentanyl and midazolam for a pacemaker replacement procedure. He is unable to walk, has many side effect listed on this site..about 10 different things, most important is his ability to walk and urinate as usual. He has a sluggish kidney an bladder. He was totally independent until Dec. 28, when this was performed. It was his 4th replacement. What will relieve these symptoms? The doctor who did this says he left the hospital perfectly fine, however, nobody tried to get him to walk as he was wheeled out to the car, and when getting out of the car at home, could not walk more than a few steps. Had to call 911 and he is still in hospital today, Jan 2.