Hi Vicky S.
Sorry that you and your O.H. find yourselves here.
Firtly, your O.H. should allow plenty of time for rest and recovery. I was very tired for the first week or so after surgery.
Yes, comfortable clothing while your O.H. has the catheter in situ. is really important. And a mattress protector will give peace of mind, in case he should have any accidents with the night catheter drainage bag. (It only happened to me once). Also, the tip of my penis became a little sore with the catheter. Sometimes it seemed to 'drag' when I moved or simply changed position on a chair. Having some anaesthetic gel like Lignocaine can help. Ask the hospital or District Nurses for some.
Also, my bum / lower pelvic area ached after a few days. I don't know whether it was just from sitting around so much, or the direct effects of the surgery. But a cushion really helped, as did having my feet raised when seated.
I would also recommend your O.H. starts to practice Kegel exercises (for lower abdominal muscles) now, so that these muscles will be stronger by the time of the surgery and when the catheter is removed. This can aid quicker recovery from incontinence (if that proves to be a problem - it isn't always). Have a look on Youtube for guidance as to how to perform Kegels. There is also an App that you can download called the 'Squeazy App' which can prompt you when your next exercise is due. (Other, similar apps are available).
Hope this helps. Good luck!
JedSee