4 years ago my sister took my mother home to live with her. My sister put my 72 year old slightly forgetful mother on a bicycle in spite of my warnings. Mom fell and broke her hip. When she woke up from the operation, mom was never the same. She was angry, combative and forgot everything before 1990 (including our deceased dad). When mom came out of the hospital my sister wanted to put mom in a home. Instead I took mom in with me for a year before she went to a home. It was terrible. Mom died 2.14.13. Can my sister be sued for putting my mother on the bike that caused her early demise? Mom was fine before and my sister was warned.