My spouse is sponsoring her daughter and have a question regarding this. The daughter resides with the father in their country and by the family laws of the country has sole custody. I know we need the declaration signed by the father. The other forms that need to be signed say to be signed by principle applicant, parent or legal guardian if under the age of 18. The daughter is currently under 18. Can my spouse sign the papers or does the father sign because he has the custody? Hope this makes sense.