As with all diseases progression and prognosis can be very different from person to person. Generally, Huntington's Disease gets worse the longer the disease is present and it generally takes the persons life in 15 to 20 years. The number of CAG repeats is basically what decides how badly the person will be affected. It is possible for people with a low number of CAG repeats to live an independent life.
People can live independent lives even if they have a disease like Huntingtons. Everyone needs some kind of help in their lives. Just because people have a disease like Huntingtons doesn't mean they cannot have a large amount of autonomy or continue to live with dignity. Health care professional should be sensitive to these patients.
Yes, people with Huntington's disease can live independent lives, because there are modern technological advances that allow people with Huntington's disease to compensate for the physical challenges that they face. Huntington's disease is terribly afflicting, but robots and other electronics can help compensate for the nerve damage and other complications of the disease.
Huntington's disease is a progressive disease. It starts out with subtle symptoms such as problems with mood or cognitive functions. As the disease progresses the patient will develop full dementia. They will also develop decline in their physical motor functions. Therefore at the beginning stages of the disease they are capable of leading independent lives. However, as the disease progresses full time care will be required.
I do believe people with Huntington's disease can live independent lives at some points in the disease. I also they should be allowed to follow their own idea's with regards to their lifestyle for as long as possible. There is a point where help is needed but that help should be requested from the individual with the disease and not just thrown upon someone. All help is good help but independence should be retained as much as possible.