My children say their father acts strangely during visitations and I'm concerned for their wellbeing. What can I do?
If you are concerned about your children's safety during the visitation you have every right, and a duty, to inquire into the problem. The other side is that the court will not regulate the day-to-day mannerisms of parents during visitation.
You should ask your children more about his behavior; exactly what is it that he does that makes them uncomfortable. If the behavior is anything that can cause your children to be placed in peril the court can impose necessary restrictions to protect them.
For example, if his behavior is such that would cause the court to be concerned about his driving a vehicle during visitation, the court may impose limitations as required to protect the children's safety. If this is a change in his behavior maybe there is a medical reason that you are unaware of. The court could fashion some method of visitation to allow them to still see him, but also protect them.
The court, however, will not terminate visitation because a child has decided that his or her father is acting strangely. You should ascertain exactly what he is doing and whether or not it actually affects the children's safety. If it does, the court can address it.