My grandfather is in hospice care on his death bed. My aunt (his daughter) has been estranged from my grandparents for 10+ years. She is ate up with guilt and grief because of all the time lost between them. It was her choice to stop the relationship and whatever the petty reason was dosent matter now. She will never get that time missed back.
Just something to think about before you cut ties with your mother. Lifes short and you only have one mother. She won't be around forever.