Or literally can't help due to the care needed or abuse meted out. The medical community can be of help If the elderly one has dementia/alzheimers and needs to be in nursing home. Many elderly ones can't make judicious decisions! Most cities have a geriatric psych facility where psychiatrists make an evaluation and assist the family in locating/transporting them to an assisted/nursing home if family is unable to be the caregiver(s). It's very difficult to deal with no matter which avenue you take.
Good to have legal and professional mental health advice/evaulations when there's different opinions of siblings/family - good for checks and balances. Court appointed trustees can be good - they have to report to court re/all of the expenditures unless the parent has handed over the reins to family or family member but at times changes need to be made. If WT cult in background or dishonest family member in charge there clearly needs to be authorities involved. Usually by the time an adult child is able to admit aged parent(s) to a geriatric psych facility in hospital or have them transported via paramedics they themselves are emotionally/physically spent.
If you're over 55 (age may differ in states) you can always contact attorneys who do inexpensive work for seniors or try for pro bono work - they farm out to reputable firms to aid those who can't afford/pay.