Depending on where she lives... (Score 1)

...there may be a Technology Access Center near her. The Assistive Technology Alliance has offices in most states, multiple offices in some. I've dealt with one in my city before and they have/know about some very cool stuff. This page - www.ataccess.org/community/centers.lasso - is a list of their centers around the US; you could check it to see if one might be able to help her, and maybe you could make a couple of phone calls if there's one in her state. I've heard buzz about new and exciting things in the speech-to-speech arena, and you could ask about that. As others have said, depending on the severity of her tremors, she might also be able to use certain specialized keyboards and/or mice. For one, Infogrip (www.infogrip.com) has some innovative stuff.