Im asking the above question as my sister who is 39yrs is behaving just the same way as my mum( who we know has mild dementia). Im having enough trouble keeping mum under "control" i dont want my sister as well. She is accusing me of keeping money from her- she gets more money than me as she is on benifits, She just spends spends. She excepts me to run around at her beck and call, arranges for me to pick her daughter up from camp then cancels me with 10 mins notice. Then slags me off to her friends. She tried to turn violent the other day but i walked away. She throws a tantrum if things dont go her way. She forgets things that weve told her then accuses us of not telling her. She even walked back to her old house where she hasnt lived for 18months last week. Her old nieghbour called me to come and collect her. She wont go to the drs as she reckons theres nothing wrong and its me thats the problem. If this keeps on i might go and find a isolated island and live on it for awhile.