Numb ness on the left side of body

My Father in law is 85 year old. He was admitted to hospital for breathless ness. He had lung infection , cough and other related issues. Doc diagonised as left enticular hear failure and high hear beat and contolled his heart beat with medicines . He was sent home after 2 days . Two days later he had severe neck pain and he was agin admitted to teh hospital , doc s diagonised as LOW heat beats. They stopped all medications for heart beat control. He was then advised a PACE MAKER . This was inserted next day . After the pace maker insersion, his left body is numb. He cannot lift his left hand  and lower limb  now. Docs now are doing CT scan.

I suspect docs have gone thru the entire procedure wrongly. They are looking at the side effects of their .Or during his 1 hour of surgery to fit in pacemaker cause this problem ? His hear beat was low , pacemaker was being implanted , so 1 hour blood circlulation was low. Hence the brain cells could get damaged. Is this poistion reversible ?