What qualifies as a dependent (a) 25 year old son/daughter making$5k per year living at home, (b) 21 year old friend going to school and living in your home (c) 65 year old mother living with her son/daughter (d) 12 year old stepdaughter living in Mexico

None of the exposed cases qualify as dependent. Qualify those direct relatives such as children, stepchildren, grandchildren, brothers or nephews under 19 years old, or under 24 if they are studying full time, and must prove that they live with the person from whom they are dependent for more than 6 months. Parents over 65 years old do not qualify as dependents, unless they have special needs or have never worked, just the fact of living with a child does not make them dependent.