what does “use a computer” mean?
sorry, but it doesn’t make sense, you asking “what would be the best device” when you said she wants to “use a computer”. doesn’t that mean she wants a computer?
what specifically does she need to do, other than browse web?
print things? play games? if so, which games? does she prefer a mouse, or would touchscreen be okay? what about keyboard? does she need to connect a USB drive? will she want to print pictures? will she want to SAVE pictures, like from email? what about video chat?
these are all important things to know…