An HSA is an individual account even though it can be used to cover qualified medical expenses of family members.
To establish your eligibility to make an HSA contribution you must complete the HSA section in TurboTax (Deductions & Contributions -> Medical -> 1099-SA, HSA, MSA). If the owner of the HSA had family HDHP coverage, that's what you'll indicate when TurboTax asks what type of HDHP coverage the owner had.
