OP, in my experience, they are decent cars. Beware that pretty much any wreck will total it because of crumple zones, but they are safer for that reason.
I had a 2000 Cavalier bought new in 1999, did develop a transmission fluid leak a few months in but was fixed in a day under warranty. Several months later I was in a wreck on the highway and that one was totaled. Got the same car again after insurance paid out, and drove that for 3 more years until my sister rear-ended someone in it and totaled it.
Several years later, the same sister bought a used 2004 Cavalier and has had no issues with it other than usual wear and tear (tires, brake pads, etc.). Still has it today.
It's not just a small car thing. Honda Civic's and Toyota Carollas of late 90's early 2000's had a reinforced "cockpit" that the Cavalier couldn't hold a candle to. Yes, if it was a bad accident, the Carolla/Civic would be toast, but the cockpit would stay intact better protecting the driver.
My friends brother was driving a early 2000's Cavalier on a snowy day when he lost control and crossed the center line and hit a Carolla head on at 50mph. He died and the lady driving the Carolla walked away with minor injuries.
I'm sorry to tell such a gruesome story, but it's part of where my opinion was formed from. The other part was buying my own car and my dad diligently looking at safety features, and in his research Cavaliers were some of the unsafest cars on the road.
I'm terribly sorry about your friend's brother, but I had a very similar wreck in a 2000 Cavalier and walked away with zero injuries. I was on the highway going 70-something, and it was rainy. Someone came into my lane without even looking and would have hit me. I swerved to avoid hitting them and hydroplaned, then hit the highway median head-on.
The entire front of the car was toast, but the cockpit was perfectly fine. The airbags went off but I didn't even need them because the seatbelt stopped me short of them.
Same story when my sister rear-ended someone at lower speeds (about 35-40). Front end pancaked, but she and her passenger were both unharmed.
I wonder if there weren't extenuating circumstances in your friend's brother's case.
I had to go back to a 2009 publication to get info on a 2002 model.
They stopped production on the Cavaliers in 2005, so most info on them probably will be older.