Suggest Treatment For Numb Feeling In Right Leg And Foot With History Of Stroke

My wife is a former stroke patient from 1996. She's had significant weakness on her left side as a result and has been using a stiff leg brace on the that left leg. She had been doing somewhat OK until up to about a year ago when she had to resort to using a walker all the time. Now as of of 12/26/14, she no longer can use the walker as he right (!!!) leg/foot refuses to move and she has great fear of falling when trying to use the walker. We now have her about just in a wheel chair. Have talked briefly with her primary care physician (internal medicine) and he think it may be a nerve disorder or disease and has referred her to a rehab specialist physician, but she can't get in to see him for another three weeks. Any thoughts on what might be her problem, and recommendation on how to proceed?