Creating Boundaries for a Parent With Mental Illness?

The best thing you could do is sell the house amd move away from her.... space is a marvelous thing when someone has Borderline..... If you absolutely can not move make sure that there are consequences for her actions..... ALWAYS keep your door locked and tell her that she HAS to call before she comes over then if she knocks at night call the police. If the police show up a time or two and she expects you to call them everytime she trespasses when she shouldn't she will stop doing it. She may throw a fit and call you names and say horrible things but you have to ignore that and stick to your guns.... Eventually if she has to face the consequences of bad behavior she will adjust her behavior.... If she threatens suicide then call the police to have them 5150 her... if she gets sent to the psych ward a time or two she will stop threatening suicide as just a threat..... been there done that with my mother..... I know it is not easy to do these things but unless there are consequences that are difficult and/or embarassing she will never change.