My Oldest Son Who Is 17yrs Old Takes Concerta,fluoxiten,& Intuniv

my oldest son who is 17yrs old takes Concerta,fluoxiten,& intuniv he has failed 2drug tests for benzos.When you look up Prozac,it states people have had false readings for benzos.Is that possible?The probation officer seems to believe otherwise.What professional fact,hypothesis,or opinion could you tell me please?I'm sorry for wasting your time.After further review I failed to realize payments are required for answers to the medical questions we can't afford to pay for them at this time.We thought they were free.Sorry for any inconvenience we may have caused.Again,thank you for your time.