I think I would try and gauge how he is doing as to whether or not he is "working a program" for any judgement basis. People staying sober or not "statistically" (JAMA Study) has little to do with what type if any program they are working and more on many other different things. If he is comfortable and sober when you drop your daughter off and he has been sober for a previous period of time leading up, it really is unlikely that he will drink. Just trust your judgement and try not and let any animosity or amores get in the way.