Some sort of longish sausage type pillow that is not too hard. After my emergency c section I found that for days afterwards things like laughing, laying on my side, holding bub etc would sometimes pull on the wound or cause pain. A friend gave me one of these types of pillows and it was a life saver. I could hold it to my tummy to provide extra support for coughing, laughing etc. Another option is (may sound silly) some big soft pads. The hossy suggested I use these to provide a bit of extra comfort to the wound (trusty old granny undies held them in place) when moving around the first few days and they were wonderful.
Or even her favorite treat, chocolate, ice cream etc.