How is the suffering we bring upon ourselves different from the suffering God gives us to mature?

In this episode Dr. Betters answers the question, "How is the suffering we bring upon ourselves by our choices different, or the same, as the suffering God gives us to mature? My sister-in-law is struggling with drug addiction. My brother wants to take comfort in the fact that God appointed her suffering, but to me this suffering seems self-imposed. Isn't my sister-in-law suffering as a result of her choices?"