Please let the treating doctor take the decision. Mostly, doctors do not go wrong in their treatment.
If there is an absolute need to operate on your father, then the Nephrologist
will definitely operate him. He may be waiting for the infection to be cleared off.
Definitely, the medications given to him will have minimal effects on the kidney
as the doctor himself knows about your father.
Please be patient.
You may also take a second opinion
from another Nephrologist, if you do not trust the present treating doctor.
I wish your dad an early recovery.