I had an ex addicted to crack. I usecto think hecwas making it up but his selfishness and crazy life got worse. It sounds hopwfully tat yiur mum is early in the crack stage. My unprofessional advise is get in touch at arms length. She is lost and clearly having a bad time in life and thatvif she wants to have a better life yiud be in it with her, but she must getcaway from anyone who has a drink or drugs habbit. It will be tough but she will get through it.
This is a really tough one and sorry your going through this. Do not ket it affect your self esteem or life. Its okay to feel uoset about this but keep your head high and sleep well knowing yiure offering an olive branch. Key is to rember its not you and she is lost. If she wants to continue in tge darkness tgis may take longer during which step back with firm belief that if sge wants a nicer life your there.
Much love xx