According to statistics from the National Institute on Drug Abuse, young adults aged 18-25 are often found to have higher rates of prescription drug misuse compared to other age groups. However, adolescents, such as the youngest brother, Dwayne, who is 14 years old, are also at risk, though typically less so than young adults.
In this case, the most likely candidate for misusing prescription drugs would be:
the oldest brother, Mark, who is 22 years old.