When in doubt, err on the side of preventing further abuse through reporting the abuse to someone who can help. The costs may be too great if the abuse is allowed to continue. Exploitation can happen to the person with Huntington's disease in a wide variety of ways. Along with the clumsiness of Huntington's disease that may make writing a check difficult, there is the dementia that may make it difficult for the patient to understand all that is happening. They may fall prey to sales people trying to convince them to invest in their schemes or to donate money to a cause.
Sexual abuse is a difficult area for many to deal with.
As Huntington's disease starts and progresses, there is a loss of the social inhibitions that we have learned to control our behavior. Thus, a patient may seek out sexual satisfaction at inappropriate times, or may be enticed into sexual liaisons that they may have wished to avoid before they became symptomatic. In addition, many patients have alterations in their interests in sexual matters. There is nothing inherently wrong with these changes as long as they can continue to enjoy their sexuality with no harm to themselves or to others. In this day and age, becoming sexually promiscuous can leads to AIDS, which is just as fatal as Huntington's disease and just as unpleasant.