I thought they have to confirm they are on the way through the app?

And if they are late or anything, how is your friend going to get in touch with them or figure out which car is theirs, or which corner they are on if they can't stop directly in front of the building? On the news two days ago, a woman mistakenly got into the wrong car here, thinking it was her Uber. The man, who wasn't ANY Uber driver, drove a couple blocks to a deserted street and tried to rape her. LUCKILY she escaped.
About a month ago, it was on the news that a guy couldn't figure out which car was his Uber, so he knocked on various car windows at the curb. A man in one car was so enrage that his car was knocked on that he got out of the car to confront the knocker. He wouldn't accept an explanation or an apology. (This was shown on the building's surveillance video.) Instead, he punched the guy so hard that when the guy's head hit the pavement, it caused an internal brain bleed, (I forget what they are called,) and he was also knocked unconscious. The puncher didn't even bother to stay with the guy he punched to see he needed an ambulance. He left. The guy was in a coma for a while and eventually died. And now, especially because the puncher was a coach for a famous football team, and had that much physical power, and left the scene of a crime allowing his victim to bleed internally, he's going to be on trial for manslaughter. People are nuts over stupid stuff.
If your friend really, really needs to use Uber, get a cheap Tracfone cellphone from any drugstore,
Walmart, Target or Staples. For $10, it comes with 20 minutes & 90 days of airtime service. Make sure it's one that can download the Uber app - as in don't get a cheap flip phone incapable of apps. Get a touchscreen model.