Anjela, have you heard about wheel chair assistance? Call airlines and tell them your mom has some walking problem so she needs wheel chair assistance. What they will do is they will pick your mom from one gate to drop in another.
As like maxy bro said make some cards with WATER , RESTROOM, KINDA FOOD SHE WANT ( VEG / NO BEEF/ NO CHICKEN) make it different color so that she recognise. Write your name and address and phone number in one paper, she nees that in immigration.
Where is her Transit ? If its in Gulf country then don't worry there will be so many nepali in airport too. Even on immigration stuff they will help.
Since she is coming to new york she will find so many dhotis too.
I will not recommend her to carry smart phone and teach whole thing. Thats too much. Unless she already know how to do it.
Don't worry my mom came like that and she said there was no problem at all. Good luck.