Another option for your mom is to try Andrea Wong's Portuguese Style Knitting.
I'm exclusively left handed - long story there - and it's by far the easiest method for me. The yarn is tensioned either around your neck or with the use of a knitting pin, and the yarn is moved from or back with a flick of the left thumb.
Check out the Knitting Daily video of Andrea demonstrating the method on YouTube here: http://www.youtube.com/watch?v=gzfYS9_t27k
It's super simple, and the video alone is enough to to get anyone started, if they want to give it a try.
Good luck, and happy knitting!