You may be right, but we both know it will not last. When things get boring and they will, he will pick the bowl right back up.
My H smoked as soon as he got home from work and usually again before bed. On the weekends that is the first thing he did even before his coffee. My S's were teenagers when he dropped the bomb and he still smoked in our bedroom and couldn't believe it when I told him that the smell followed him down the steps. After he left I found out that S19 was pretty sure his dad was the one smoking and S17 suspected. When S17 heard for sure from his brother he cried.
Pretty crappy, huh.
Everything happens for a reason, maybe Dad needs to find that it isn't better out there, he needs to realize how good he had it here. Maybe he will find God and that is the most important thing when he finds Him he will know he is supposed to come home.