Mightmouse is right... It will get better. It's very early after surgery. I can't speak to the orburator, but the neck neck dissection does cause numbness, and I can understand why after her surgery she is having trouble eating - it will take her a while to recover fro the whole thing - but she should eat - that said make sure she's taking in the high calorie boost / ensure - add in some protein powder if you have to - she needs more protein now for healing and will for the upcoming radiation. A walk even a short one is good, active exercising would be hard this point though it might increase her appetite. I walk my dog twice a day - and even though I really don't have an appetite that makes me hungry.

Sorry about the distance you feel, but your mom is probably still quite traumatized and worried about her upcoming treatments, and everything new going on in her mouth. It will change eventually - just hang in there. You sound like you are doing everything you can - I know it's hard not to nag, but a little nudge or a walk with her would help.

Take care and good luck - radiation is a bigger recovery than surgery - but she'll get through it some how.