I agree mostly with this but before you get involved with this make sure you really understand the 5 stages of grief. It sounds like he's going thru depression. So if you do say something be prepared for anger mostly. And don't take to heart anything he might say. In order to make better choices about the pot he needs to be in a healthy state of mind. I would just let him know that you are aware ( you can never understand someone else's grief) of his loss. Ask him if he can make sure his Windows are closed so he is not likely to upset any neighbours with it and I would invite him over for dinner. Don't push him to join you and if ur declines like most people will drop off some left overs so he's aware that people do care about him. It might take some time for him to start talking. It's then and only then will he be more understanding about stopping the pot.