How sad, and the seat collapsing and ejecting a driver wearing her seatbelt is extra scary.
The wide molding along the side is a good clue for the Olds or Pontiac minivans. Pontiacs tend to have the biggest body side molding for some reason. I had an '88 Grand Am with huge molding on the sides and it was a great trap for dirt, road salt and moisture.
I've heard of the driver's seat collapsing backwards in some vehicles when they were rear ended. A couple of years ago in my area, a mom driving her Saturn was rear ended and her driver's seat collapsed. IIRC, the mom survived the crash but her young daughter riding in the back seat was killed. Another daughter in the back seat survived the crash. It was right around Christmas time and the mom and her daughters were on their way to go Christmas shopping.
My BIL also was rear ended in his Saturn SL1 several years ago by a teenager driving a Dodge Ram pickup. BIL's driver's seat collapsed backward and he was knocked out. He had a concussion and does not remember the actual crash happening. He remembers leaving work for the day and then waking up in the hospital. Fortunately he was otherwise okay. We were also glad he didn't have any rear seat passengers because they would have been severely injured or worse by the collapsing front seat and my 6+ feet tall BIL landing on them.