i think thats a good idea too. though i think deep down, he loves you but his addiction may be in control. being a ra, i know how hard it is to do the right thing when drugs is calling you. the drug seems to have a voice with a mind of its own.
that being said, i think the best thing you can do for him is to protect yourself from his addiction, in turn, allowing him to suffer the consequences of his actions.
i'm now 7yrs clean but it took for my family to get out of my way and let me fall, then and only then was i able to see for myself how destructive and out of control my life had become, causing me to want desperately to get sober and stay sober. today i'm totally grateful that they did, otherwise i'd probably still be out using, in jail or dead. today our relationship is better than it was before the drugs.
i know this has to be hard for you but i honestly think it may be the most loving thing you can do for you and your son. you both are in my prayers.