Complex sentence: After relapsing into drug abuse, Kosilek became a patient in a drug rehabilitation facility, and there Kosilek met Cheryl McCaul, who was working as a volunteer counselor.
Split into simpler sentences: After relapsing into drug abuse, Kosilek entered a drug rehabilitation facility as a patient. There, Kosilek met Cheryl McCaul, who was working there as a volunteer counselor.