(apologies for such a long question)
before she died, (40 years ago)my mother made me promise to " look after my (adult) sisters, as I was the "strong one"i kept my promise, but a sister just two years younger, was, for decades a manic depressive, yet despite having my own family/business/ marriage difficulties of my own I always looked after this sister, financially and emotionally. she ruined every celebration either before/during or after by crying and we all sat round her trying to "help/support" her. her husband was also a manic depressive, always threatening suicide. eventually they split up, and she found a new boyfriend. this man didn't want her son around,(17 yrs) and drove him away, to live with me.no request he just turned up. he was also a maniac depressive.in his suicidal state cried that all his life my sister had told him I was the black sheep,(sister went to grammar school, I ended up in an approved school) and a disgusting parent and so on. the bottom line is, that my daughter said unless I wrote to her and told her I didn't want to see her anymore, for the stress she had caused for decades, she would ring her and tell her all about her husbands girlfriends etc,I was afraid that she would, and my sister could be totally destroyed by the information. so I wrote the letter,
the bottom line is that 15 years have passed, and time is running out for us all, and I want to make amends. I asked if I could see her a few years ago, when she was very ill, but she simply said "it's not the right time".what/how, if possible can I resolve this sad issue.