Setting healthy boundaries and confidently following through with them is not easy and requires reflection, work and practice. But it is a strategy that provides support during the difficult times, especially when addiction is present.
If I had to characterize pot users in one sentence I would describe them as observers of their own life. This passivity cripples ambition and motivation. However, a strong relationship keeps the bridge open between you and your loved one, and this will be vital when they signal a desire to change.