I was always under the impression that he was mainly known for the drums on Waterloo, Dancing Queen and all the big Abba hits, and that he was revered on here mostly for his playing on those records. I don't know if the HOD members were also under the same impression?
It turns out he joined Abba later. But the drummer (now deceased) that played on Dancing Queen, Waterloo and pretty much all of the other big hits we think of was someone called Ola Brunkert, who was with Abba from the start in the 1970s up to his last recording with them in 1981. I'd never heard of him before today. Here's Ola Brunkert playing on the original drum track for Dancing Queen. One thing I noticed is that on the actual full song recording, there's an emphasised hi-hat slice throughout the song at various places, always on the and of 4. But that's not played on the isolated track. So maybe they overdubbed that? Actually, the more I listen to it, the more I'm not sure if it is the original drum track, some of the snare hits sound different.