If a daughter in her 40's is unable to work due to her responsibilities taking constant care of her father with cancer who is undergoing cancer treatments, as well as, her mother which has dementia. Is there a service, Medicare or Medicaid, which will pay for her services?
Lastly, please consider that daughter can't count on inheritance or estate -- one or both parents could have to move to skilled care and this will quickly eat up the estate such that she may end up with nothing much for her years invested in their care.
I don't like to sound callous, but their are countless posters here who have provided care to loved ones and then can't stay in house (can't afford to keep it) or can't find employment, don't have healthcare, retirement money, etc.
Might be better if she works and hires care for parents and she just helps as she can.