When I looked for videos of the Mercedes L3 in action a while ago all I could find were videos showing it doing stuff the Tesla FSD could do easily 5 years ago. Has it improved a lot recently?

The mercedes L3 thing is a gimped press gimmick/vaporware. You won’t a single non-press video from an owner just using it. Not a single one.

can you show me how to order a vehicle with this drive pilot?

I'm sure you know more about it than I do. I'm certainly not an expert.

I can say though that when my brother bought his first Tesla he paid thousands of dollars for FSD, which was supposed to be released "any day now." It's been many years and as far as I can tell it's still not REALLY here (in the sense that most people would mean it).

I know that the plural of anecdote is not data, but... The Tesla that he bought originally all those years ago is actually gone now. He had one of the earlier versions of FSD enabled and passed out behind the wheel. Tesla, in their infinite wisdom, decided that if you let go of the wheel for too long they should just completely disable the self driving (at least in that version). So naturally when the driver became incapacitated it just disengaged self driving completely and let the vehicle drive straight into a tree as "punishment" for daring to let go of the wheel for too long. Nobody was hurt, but the vehicle was totaled. It could have been much worse though.

It's such an obvious design flaw. "Driverless 2000 pound missile hurtling down the highway at 55 mpg" is the one failure mode you would think they'd avoid at all costs, rather than using it as the safety fallback. When people talk about how great Tesla engineering is I just kind of shrug.

This is completely made up and/or your brother lied. Teslas always came to a slow stop if no driver attention was detected. Originally just slowly stopping in lane, now actually pulling over.