Other Employment-Based Greencard/I-140 General Issues

If you parent(s) are deceased, illiterate, disabled, etc. and unable to therefore sign an affidavit regarding your birth, then it would be beneficial to write an affidavit yourself swearing to the fact that your parent(s) cannot write an affidavit and why.  You still need two affidavits by close relatives attesting your birth, in which case aunts and uncles that were present when you were born may be the next best alternative.  Older siblings may be used, but they would have had to been old enough to conceivably remember your birth.