You need immediate help from Fife council, you should be getting carers coming in a couple of times a day, you getting paid carers allowance/attendance allowance? Its not much, but still something. Similar happened to me with my 'so called' sister walking away from the whole thing. I don't have a sister now. she is dead to me. I was lucky though as my Mrs is a retired nurse, and she has been brilliant, I'm working full time so I couldn't cope with it, it's just too much.
All the best, Dundee city council were a good help to me, hope you get the same help/support from Fife.