I would recommend the following:
Upper body ergometer
Upper body resistance training doing it in a circuit fashion
I would also add balance training and core training for this individual. This will stimulate the neuromuscular system to help prevent injury and unwanted joint motion. It will also enhance neuromuscular efficiency for more intense exercises later on
The biggest thing is a workout needs to be one that they will enjoy and stick with ( even with limited mobility). Keep it challenging yet feasible for the client.