How would i know when my elderly parent needs assisted living facility?

Assessment of ADL.: This can be very difficult. Firstly, would start the conversation with the parent's physician; can parent still take meds on own correctly and safely? There is an instrument that makes a full, geriatric assessment which measures the ability of person to carry out activities of daily living; usually done by nurse trained in this area. Most elderly will resist going to a 'home'. Get professional help.