Conversation so far:
What is the death of Carl for the Beach Boys?
In early 1997, Carl Wilson was diagnosed with lung and brain cancer after years of heavy smoking.
Did Carl Wilson receive treatment for lung and brain cancer?
Despite his terminal condition, Carl Wilson continued to perform with the Beach Boys on its 1997 summer tour while undergoing chemotherapy.
Did Carl Wilson's terminal condition affect his performance with the Beach Boys on their 1997 summer tour?
During performances, Carl Wilson sat on a stool and needed oxygen after every song.

Question: How many shows did he perform like that?
Self-contained rewrite: How many shows did Carl Wilson perform on a stool and needing oxygen after every song?