Adult child with disabilities

If he has earned income he will file his own return ... you cannot add his W-2 on your return.  However he may still be considered your dependent if he qualifies ... 

Who can I claim as my dependent?

You can claim a child, relative, friend, fiancé (etc.) as a dependent on your 2017 taxes as long as they meet the following requirements:

Qualifying child

·         They are related to you.

·         They aren't claimed as a dependent by someone else.

·         They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.

·         They aren’t filing a joint return with their spouse.

·         They are under the age of 19 (or 24 for full-time students).

o   No age limit for permanently and totally disabled children.

·         They live with you for more than half the year (exceptions apply).

Qualifying relative

·         They don't have to be related to you (despite the name).

·         They aren't claimed as a dependent by someone else.

·         They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.

·         They aren’t filing a joint return with their spouse.

·         They lived with you the entire year.

·         They made less than $4,050 in 2017(not including SS benefits).

·         You provided more than half of their financial support. More info

When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.

 There is also no income limit for a "Qualifying Child" dependent.
A child of a taxpayer can still be a “Qualifying Child” (QC) dependent, regardless of his/her income, if:
1. He is under age 19, or under 24 if a full time student for at least 5 months of the year, or is totally & permanently disabled
2. He did not provide more than 1/2 his own support. Scholarships are considered third party support and not as support provided by the student.
3. He lived with the parent (including temporary absences such as away at school) for more than half the year
 
So, it doesn't matter how much he earned. What matters is how much he spent on support. Money he put into savings does not count as support he spent on him self.
The support value of the home you provided is the fair market rental value of the home plus utilities & other expenses divided by the number of occupants.
 
Furthermore, there is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim his own exemption. If he has sufficient income (usually more than $6350), he can & should still file taxes; he just doesn’t get his own $4050 exemption (deduction). In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.  
Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.

That depends. Parents do not have to live with you as a member of your household all year to claim them as a dependent. However, the person must have gross income of less than $4,200, and you must also provide more than half of their total support. You need to sum the amounts of annual rent, medical, utilities, meals, etc. and determine if your contribution exceeds half of the total cost. If this is the case, you could be entitled to the Credit for Other Dependents, which would reduce your tax liability by $500.

 

Claiming a Parent as a Dependent