What might the recovery time be if someone were to have one kidney removed?

A friend of mine is scheduled for the removal of either part a kidney or the whole kidney due to a cyst that is growing both inside and out of it. From appearances using the MRI the doc sees that it is likely cancerous and will not know more until further examination. The surgery will be robotic assisted and will last approx 3 hours depending on what they discover during the operation. My friend does not think the down time will be very long however I thing it might be more than a month or so --I want to make time available during this period to assist her as needed. She is optimistic and believes the re-cooperation time is minimal-- I do not want to be pessimistic and let her know the down time might be longer than she anticipates. I would like to be available for at least two months not two weeks--anybody have any ideas on this