You are very welcome. I also suggest you read the sticky posts at the top of this forum. There is a LOT of really helpful information there.
It's good that he appears to be serious about recovery, but, and I hesitate to say this, you should be, at best, cautiously optimistic. I am not addicted to drugs, but I am an alcoholic and know from experience that it's a very safe and secure feeling being in an in-house recovery setting. It is easy to be gung ho about recovery while in rehab; but, it's once he is back in the real world that the hard work will start.
Please don't expect him to come out of rehab a well person. He won't be. But, he will have the tools to work his recovery, and it's something he is going to have to deal with on his own. YOU take care of YOU.