quintuple bypass surgery complications

My father-in-law had quintiple bypass surgery 7 days ago. he's 83yrs old, still in ICU, not yet off ventilator, and now needs dialysis because kidneys are not functioning properly.
what is the prognosis? what should we expect? does this type of complication occur often? will his kidneys recover? when will he get out of ICU? will he need dialysis for ever? will he recover completely and when?

[Cleveland Clinic]

Based on the fact that he is still vented and the kidneys have failed, his prognosis is poor, but not dismal.  I don't have an answer for all those questions that you posed because this is very difficult to predict.  I hope that once the dialysis kicks in he'll be able to come off the vent, if he doesn't develop an infection, and maybe once he's off the vent his recover would improve.  This is not a common occurrence, however, in someone who is 83, the risk of it is much higher than is someone much younger.  Lets hope that the dialysis kicks in and helps improve his volume status.  It is not unheard of that his kidneys may recover enough where he may be able to come off dialysis.