There has to be more to the OP’s story. Having family in another country is not a reason for denying a TS.
That was my immediate thought, too. And I know fellow CWOs who have family in Iran, Russia, and China with TS/SCI at that. Something else is definitely up. Hell, I have relatives from three foreign nations myself, and was favorably screened for and received a TS clearance.
I have, I had a candidate for nuke who was denied as his father still lived in Vietnam, I worked for a LCDR and his father in law was in the Japanese government and he had his clearance suspended for many months until they did a very detailed investigation.
It's an extreme case, but the DOHA appeals board has held that one relative in a foreign country is enough to DQ you. It's whether or not that family can be used as a tool to make you a risk for exploitation/coercion by the government of that country. They take into account how adverse that country's relationship is to the U.S., what the family member does for a living (government employment makes it worse), the closeness of your ties to the family in the country, and how frequently you're in contact with them.