My father is a principal on a qualifying labor certification application that was submitted before 4/30/2001 does this help adult unmarried daughter.

As your father was the principal on a labor certification with merit filed prior to 4/30/01, your sister who was under the age of 21 at the time is grandfathered for purposes of §245(i) if she entered the US by December 21, 2000. That means that she is not barred from adjusting status through any means that she can gain immigration from even if she entered the US without inspection or took up unauthorized employment or overstayed her visa status. For purposes of accompanying or following to join your father on his case, she would be too old by this time. You say that your sister has a US citizen daughter who will be turning 21 in a couple of years –that petition would likely be the quickest way for her to immigrate. Usually, an immediate relative petition like this would take approximately one year to complete. A sibling petition begun today on the other hand could take approximately 15 years to gain permanent residence. Due to the limitations of the Lawyers.com Forums, Alan Lee & Arthur Lee, Esqs.’ (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.