Elderly parents

I'm having agonies over this situation but I know I am not the only person to deal with this so I thought I'd ask for your views. My parents are now in old age. My father has always been domineering and controlling (and frankly has ostracised every family member - me included) but my mother stood by him and they are still together in their own house. She has had a series of falls recently due to low blood pressure plus she is starting with senile dementia. The GP is concerned she is not receiving the care she needs. The GP also is concerned about my father and wants to do a mental health assessment due to his violent outbursts (verbal not physical). I live far away from my parents (and can only get to see them once per month), so I'm really pleased that their needs have been noticed and action is being taken by the GP but I need some advice about how this is likely to work out. If father is deemed to be unable to care for mother what will become of them? Has anyone else got experience of this that they can share? I know all family dynamics are different but I just hoped to get some support from someone who has been through a similar experience.