Generally speaking, the family members who live with you and are dependent upon you for support at about 50% or more of their total available funds, they might be considered to be your dependents if no one else is claiming them, including themselves. The Turbo Tax app will entertain this and give you help during its discussion of deductions. If you select to add more dependents and follow the instructions you will be able to list the potential dependents and the app will help you to discover whether or not you can claim them.
A dependent does not have to be an immediate family member or even a family member if you can show that they are dependent on you more than anyone else including themselves - and that no one else can or will be claiming them.