Complex sentence: He was treated at the shelter and appeared to regain consciousness, and the cause of his collapse was initially revealed to be a case of the flu, however evidence in later episodes points to it being a more serious respiratory ailment.
Split into simpler sentences: He was treated at the shelter and appeared to regain consciousness, and the cause of his collapse was initially revealed to be a case of the flu. However, evidence in later episodes points to it being a more serious respiratory ailment.