Conversation so far:
Was Tōru Takemitsu interested in music from an early age?
Tōru Takemitsu first became really conscious of Western classical music during his term of military service.
How did Tōru Takemitsu's aquaintance of western music affect him?
Tōru Takemitsu felt a need to distance himself from the traditional music of his native Japan that for him always recalled the bitter memories of war.
What other influence did western music have on Tōru Takemitsu besides feeling the need to distance himself from traditional music of his native Japan?
Despite his lack of musical training, and taking inspiration from what little Western music he had heard, Tōru Takemitsu began to compose in earnest at the age of 16.
How did Tōru Takemitsu characterize western music?
What years was Tōru Takemitsu's military service?
What did Tōru Takemitsu do after leaving the military?
During the post-war U.S. occupation of Japan, Tōru Takemitsu worked for the U.S. Armed Forces, but was ill for a long period.

Question: What sort of illness did he have?
Self-contained rewrite: What sort of illness did Tōru Takemitsu have during the post-war U.S. occupation of Japan?