If you cannot get them to share their 2015 AGI amount with you, you will not be able to include that amount of AGI when asked and ultimately your tax return will be rejected when you go to efile.  The IRS requires everyone to include their AGI's from the prior year, and married filing separately individuals to indicate their spouse's AGI, in an effort to prevent the fraudulent filing of income tax returns using other people's social security numbers.  So, if they will not tell you what their AGI was,the only option for you is to print, sign, date and mail in your tax return.