I am trying to determine if it is possible to claim an undocumented alien as a dependent for tax purposes during 2017 in the United States (form 1040 line 6c) as well as a credit for money spent for their care (form 2441).
Background details: The person submitting the tax return is a natural born US citizen. The dependent is their grandmother whom has been residing without documentation in the United States for approximately 70 years. The dependent has no income and is unable to care for themselves. The dependent lives full time with the filing individual and is cared for full-time during the day by a medical professional, paid for by the filing individual. The dependent does not have an ITIN and is currently in the final steps of naturalization and will have their US citizenship at some point in early 2018 but they are currently considered "illegal" and do not have a green card / visa / other documentation from the US and also do not have any relationship / passport / other documentation from their home country.
I believe that they qualify as a dependent based upon step 4 in the instructions for line 6c, due to their status under question 2 and the application of the substantial presence test for US Resident Aliens outlines in Pub 519. It then follows that once they are eligible to be claimed on 6c, form 2441 is naturally appropriate. Is this a reasonable interpretation of the guidelines? I notice that the description of dependents always uses the term 'person' rather than 'citizen' or 'lawful alien' so I believe I'm in line with the requirements as stated. Additionally, should (can) the dependent be listed without a SSN (as they do not have one) or should form W-7 be filed to request an ITIN?