UPS currently does require a drug screening before they hire you. This guy said he's been there 10 years and they didn't that long ago. If you have an accident they can require you take a drug test, you can refuse but thats grounds for termination.
I find it hard to believe he drinks or get high on or before the job. The job is way to tough to be done that way. Plus to drive that truck requires a good bit of attention, not to mention backing.
Many of the things he says are true, but stealing, drug use, abusive behavior toward a customer or employee, and just hanging around during the day are not tolerated at UPS. They can tell who is working and who is out there wacking off. The guy wacking off will be followed, photographed, and then fired.
It is a very hard job. You must have good driving skills, good work ethic, and good people skills.