What is the difference between someone demand for physical therapy and his need for physical therapy?

To answer that question you must first ask why does someone need physical therapy: to obtain optimum function and quality if life for his/her condition. So someone demanding might be someone that feels entitled to therapy even though his optimum function/pain control has been obtain (entitled demander), or he/she has not been made fully aware of his optimum level, thereby thinking he/she can still improve Where someone that needs therapy, is where the therapist can still gain more function by decreasing pain, increasing strength etc (depending on diagnosis and reason for consultation).

Demand is what patient wants and need is the actual need decided upon by expert practitioner, such as doctor on clinical judgement