Dear Naimnut, My husband did not have di vinci, but rather
open surgery, so not sure if this is helpful.
With help from lawink below I've done some calculations and prior to recent surgery Naimnut, my husband was in the higher ranges of weight, and has always been "classified" as overweight for his height, according to most tables. He lost about 30 pounds prior to surgery, and felt generally good and fitter. He has (thankfully) been fully continent with no leaking since surgery.
Re. exercise, my husband can't exercise the way others do, so he did not do nearly as much exercise as others would have, but he did what he could at the time and after . I believe therefore that it is also the attitude of hope going into surgery that assists healing, not just the physical preparation beforehand. We personally had to have this attitude, as my husband also considered he was a little out of shape too.
However he flew through the recent experience of prostate surgery with his attitude. I am not sure if this is relevant, so please just take whatever is helpful as I realise your situation may be completely different, however my husband is of similiar age.
All the very best of luck to you and your wife.