What Can Cause Delayed Recovery After By Pass Surgery?

84 year old man, never a health issue, exercises daily eats extremely healthy. 9 months ago starts to loose weight and begins to have difficulty in normal daily activities. Family becomes concern and sets the wheels in motion to figure out what is wrong. Come to find out that this man needs a triple bypass. Has the operation. The first three days out of surgery no problems, gets moved out ICU. Day four has episodes of V-Tach and then that night codes. After 25 minutes doctors revive him. They keep him under sedation and something called a cooling vest for the next 24 hours (amongst other machines like a respirator) and quite a few I.V. meds. Day 5 he slowly wakes and before an assessment for the possibility of brain loss he goes into v-tach that they can no longer control with the external pace maker. They make an emergent decison to implant a devise that night. He makes it through the night. Once the sedation wore off the next morning (day 6), his v-tach episodes return so then the docs make another decision to go in and preform mapping and ablation. Day 7, the episodes still occur but not as intense, docs are letting him rest over the weekend and then will reassess on monday. His condition hasn t worsened but hasn t improved either. What are his chances?