For folks who may track along later -- It all varies WIDELY by the various Rehab Centers.
So you sort of have to check them out.
The Rehab where Mrs. Hammer went had nothing for our family -- pretty bad in that regard . . . but the Rehab near us, where I help do the Alanon Family portion (a "help others" thing for me), runs a Real Nice family program twice a month, and even some special program once a month -- Just For The Kids.
When your step sons get a little older maybe look into Alateen for them. In general, Alateen is for 9 to 19 year olds, depending on location. It was/is VERY helpful for our two oldest kids. (now 11, 9, and a we will see about the 6 year old when he gets older).