If a dependent is living outside of the US for more than 330 days in a year, they are not subject to the Affordable Care Act requirements and you won't have a penalty for them. You need to file exemption form 8965 to claim the exemption.
In Turbo Tax, you would indicate that they did not have insurance in 2015. You would also indicate that they were not required to have insurance because they were a resident of foreign country or U.S. territory. (see screenshot below)