why not write down your questions and concerns before the meeting. then contemplate which are the 3 or 5 most important to you.......he'll still be going thru some detox/withdrawals by then and not completely stable and sane. so don't expect too much.
and just as his detox/recovery is going to take TIME....so will your own healing. those feelings of frustration, anger, disappointment, rage will not simply dissolve in a few days. they are YOUR feelings, and all of them are valid. you will have to decide how YOU choose to deal with them, rather than just wish them away.
it takes work, but you are worth it!