A band playing with more than one drummer can be tricky, if they're not totally in sync all the time, and they can overpower the rest of the band if the mix isn't right. The Grateful Dead, the other prominent rock band that employed two drummers, often had problems in that regard, especially in Mickey Hart's first tenure with the band in the late '60s and into 1970. When Mickey returned after a 5-year hiatus, he and Billy Kreutzmann were much more like Trucks and Jaimoe: in rhythm and more in the background, where a good rhythm section should be. Honestly, there were times with the Brothers when you really couldn't tell there were two drummers playing. That's how seamless Butch and Jaimoe were.
Anyway, RIP to one of the great drummers who ever lived.