Complex sentence: On November 15,2017, Åhr's manager went to check on him in preparation for that night's performance at a Tucson, Arizona venue when he was found unconscious and unresponsive in his tour bus.
Split into simpler sentences: On November 15,2017, Åhr's manager went to check on him prior to that night's Tucson, Arizona performance. He was found unconscious and unresponsive in his tour bus.