havesomeseichel,
it seems this person has some sort of psychological disorder. In squeak’s absense I would stress that you listen to his advice above – don’t let his/her talk affect your self esteem. If some of the accusations are so crazy then don’t take ANY of them seriously and never let that person convince you that things would be so much better if you didn’t exist. Also, like squeak said, its not your job to fix that person, its only your job to control your reaction, which should be to laugh inside at the ridiculous things this person is saying. I hope this helps. Having dealt with such people I know its easier said than done to not let it affect you, but you can do it. Hatzlacha!
and BTW, if its your spouse or parent then try to go for professional counseling or speak to a rav who knows you, even if that person won’t come along.