Seen plenty of alcoholics with TS clearances.
Yep.
The investigators ask whether people who knew the applicant has ever seen them “out of control” which means so drunk that they could not control what they said. If the answer was yes, then no clearance.
Now, if the person was applying for permission to work around nuclear weapons, the use of alcohol is more problematic. Each year this is reviewed and about 10 % lose their clearances because of alcohol induced behavior that was noticed and reported.
The point is that if the clearance was for work that was at a low level, they could skate by with some alcohol problems well into the past. If the problems were currently being reported they would likely fail to get the clearance.