If a parent gets his adult daughter a hair follicle drug test?

The results will go to whoever ordered the test. The testing company won't even KNOW the subject has probation officer.

Nothing is automatic. 

The results of the test, if done by a medical professional, are protected by HIPPA and won't go anywhere without her permission. 

A test purchased at a retail store will go anywhere her father wants it to go, but she is not obligated to consent to the test. 

A parent has no right to get a hair follicle test on an adult daughter. Only a court ordered or police test would stand up in a court of law.

No. If your dad commissions a private test then the test laboratory only provide the results to your dad.

The P.O. or other law enforcement personnel are only going to learn of the test if you or your daughter tell them, and even then they’d still need a very good reason and a court subpoena to force the laboratory to disclose the results to them. Even then it could be fruitless as many (most?) private labs deliberately do not keep copies of results for long after issuing them.