Wow... excellent question.
I would say that if they are using weekly, they are still considered active, but that's just my opinion. There are a lot of factors that play into this. Are they enthusiastic about the rehab? Are they doing any kind of reading at home, either from the big book or some other literature that the rehab would have referred them to?
I guess the only person who knows whether or not they are really trying is the addict. Sometimes I think the labels we give them are less important than the actions that earn them one label or another... but I'm no expert on that issue.