Either parent can enroll the children in summer camps... however, the parent's should be respectful of the time commitments on the other parent.  With that in mind...Your son has a couple of different options depending on what is best for him and the children.His first option is to not take the children to the camps.  Unless there is a court order otherwise, he is entitled to do activities with his children that he so choses during his time. He is not bound by the decisions of his wife.His second option is to take the kids to the programs, give them a shot, and then leave if the kids are not having fun. This way, he can argue to the judge that she was not effectively co-parenting with him... but he was working towards co-parenting with her.His third option is to work an agreement with his wife where she got to keep the kids on the days the camps are planned and then he would take other days.  This way, he still gets his quality time and his wife is stuck with toting the kids to the camps she arranged solo.  This teaches the wife to be accountable for her decisions....as she will be expected to do the left work when she does.His fourth option is to seek a court order that sets out a set of rules who does what in sucha a way that respects the other parent's time.These options can be used together or separately.  He may want to visit with his family law attorney before deciding on the actual combination.