Affidavit of Child in Support of Motion for an Order for Sibling Placement or Contact. MC A3 Affidavit Whereabouts Unknown (PDF).Much confusion surrounds the need to submit I751 affidavits and how to write them. We explain and provide an I-751 affidavit sample. Our office probates wills and processes intestate estates (estates without wills). How well the person providing the affidavit knows you; c. The names of both of your parents; d.