Let your mom do what she wants! It's not as if she will be able to concentrate on anything else while this surgery and initial recovery is happening anyways - it's just as scary for her as it is for you. Being there will let her be in on the status updates that much quicker. Make sure she knows it's ok with you if she goes away for a rest whenever she needs it and feels comfortable enough to do so.

I only had about an 8 hour surgery, but I certainly wasn't able to communicate for a long while after I woke up. I was groggy, disoriented and frankly not sure how much I could move around without yanking something important out, because I was connected to so much stuff (trach had an oxygen tube connected to it, I had a feeding tube down my nose, an IV, a monitor clipped to a finger or toe, a catheter, a huge amount of gauze and wrapping over my wrist, and a stupid cardboard French fry container looking thing taped over my thigh where they took the skin to replace the forearm flap skin).

It would be nice to have your mom there once you're out of surgery and in a recovery area or step-down unit to bring you a dry-erase board with marker and a rag to erase, or something else to help communicate your needs. I recommend this item over an iPad because of theft concerns, and over a pen & paper because I found the nurses just took my pen with them after borrowing it, leaving me with nothing to write with until my sister brought me the dry erase board. If theft isn't a concern at your hospital, the iPad is probably a better option.