First, is the she using a suspension fork? If not, get one - an air model would probably be best as it will give infinite adjustability. Second, install a fatter tire, like a WTB Mototraptor 2.4 and run it at a fairly low pressure. Third, I agree with the Oury recommendation - very comfy grips, best out there in my opinion. Fourth, try some glove with gel padding in the palms.
Also, if she isn't running bar ends, you may want to try installing a set so she can switch hand positions during the ride. Finally, I'd suggest having her get fit for her bike to make sure she has proper positioning and is not putting too much weight on her hands due to her bike set up.j