Helping those that do not help themselves

How do we assist someone who does not want to or have the desire to help themselves? On a recent placement one of my patients who was morbidly obese with severe arthritis of most of her large peripheral joints which in conjunction with each other and her lack of motivation had resulted in a severe loss of function.
On the second time that I visited her I found that she would rather blame her lack of mobility on everything else other than her weakness, escessive weight and lack of motivation. In the public health sector, resources and staff are stretched to full capacity as it is, there simply is not the time or manpower to do everything for these patients and treat them on an ongoing basis.
I know that this particular patient may have thought I was a little cruel but I refused to be lenient as I knew she had the ability just not the motivation or the determination. When pushed this patient could get up and walk to the physio gym from her ward rather than be wheelchaired. On one particular session I managed to push her to walk 250m after she had previously been to or from the gym. On subsequent session, the patient displayed utter disgust and shock when I arrived to her room without the wheelchair in tow. She complained the whole way but I didn't care, she was safe and stable which was the most important thing. The only reason she was still in hospital was becuase of her weight and her instistance that she was not ready to go home.
She could abuse me or any other physio all she liked but we are only trying to ensure that she receives the best health outcome. Sometimes shock tactics is what is required to motivate people or to get them to take ownership of their own health. No one else is responsible for their lifestyle and health choices. She may like the nursing staff that come round to see her rather than physio but it is not their respoonsibility to know what specific areas this particular patient needed addressing in.
At some stage treatment and care for these patients has to cease, but when? However it is a fine line between ceasing treatment completely and maintaining treatment to prevent readmittance to hospital. In such an instance what do you do?
In the end the patient was discharged much to her disapproval and was provided with rehab in the home to focus on functional goals within a contextual setting. Quite frankly I was glad she had left because I felt that there were so many other patients that could of benefitted from my help, I really didn't see the point in wasting my time, her time and resources on someone who was draining the system.