I just got the cathater out from my open surgery done on the 24th. I can tell you my experience, which may not apply to your husband.
I entered the surgery room at 720am, was awakened in the recovery room at 1030am, and was in my room by 12:35pm. I had a right inguinal hernia repair done along with the prostatectomy, so that added 30 to 45 minutes or so of surgical time. I asked for and received a bladder spasm suppository in the recovery room, which eliminated any discomfort I had. I recommend you discuss with your surgeon doing this, along with a prescription to take home for as needed use. The pain level from recovery room to discharge time was maybe a 6-7 immedialtely after I got to my room, but the nurse gave me a painkiller shot in the iv, and took care of that. After the inital pain control, pain stayed in the 3-4 area the rest of the day, and was mostly gone the next day. Any pain left was from movement, and easily tolerated as it mostly stopped when I stopped moving. lol The incision was 5 inch long, centered midway between the belly buttom and pubic bone. Mine is stitched internally with dissolvable threads, the outer is glued together, makes a nice clean barely noticeable scar, I am thinking. I had a drainage tube on the left lower abdomen, which was painlessly removed the day after surgery. It left a pea sized opening which has scabbed over and is slowly sealing and filling up. The surgeon placed a On-Q lidicaine numbing pump with a tiny line running and laying down in the glued incision. It was a real value to keep the incision numbed for 48 hrs. The amount of cutting is about the same as the robotic 5 or 6 cuts they make, if you total the length of them, so I don't consider that a factor. The advantage of open, is the doctor gets a hands on technique for removal, and I think there's a better chance of truly evaluating the surrounding margins and bed by both sight and feel Personal opinion, of course. I was on my feet and walking 5 hrs. after surgery. I began drinking as much water as I could stand, after all you are on a catheter bag, this flushed out clots, blood and left overs from surgery. Drinking all you can and walking is key to a quick recovery and fast discharge from the hospital. I walked 2 times that night, was on light soft food the rest of the day of surgery. Next morning, I was allowed a regular diet. I managed to keep a low grade fever for 6 days, which is a couple days longer than expected during recovery. I had some amount of swelling and bloating in the abdomen, most of which was relieved first with the initial passing of bowel gas (where does that much come from in such a short amount of time) lol , and later with the first bowel movement.
That morning I walked, got to know my limitations with the cathater, got some home care instruction for wound care and cathater care. I was discharged late that afternoon. I was sore for 2 days, had low range pain for 2 days after discharge. Nothing agonizing in either case. After the 3rd day I felt probably 80% back, as far as pain and soreness. I was back to full mobility, almost full stretching and pain free after 4 or 5 days. I showered the day after I got home, which was the 2nd day after surgery. No baths or hot tubs for 4 weeks. At that time, all the dressings came off and the On-Q pump line came out, when the dressing did. The wound is healing fine, and is almost complete 11 days after surgery. It is no problem and no pain. Any limitations I had after surgery was created by the cathater and bag. I am on a 5# weight restriction for 4 weeks, then go to 10 lb for 2 weeks and full release after that.
I don't know if the robotic would be easier, but I do know that the big issues for me after surgery was the inconvience of the catheter rather than the open surgery wound and recovery. I suspect I would have felt as good/miserable with either procedure. I hope my experience helps you in your surgery preparation.