Actually, yes you *are* the head of your household, according to JW teachings, even as an "inactive" person, even as a "disfellowshipped" person, even as a "disassociated" person.
You can forbid your children from attending meetings. However, you might want to try reaching a compromise that causes the least friction, since the elders will urge your wife to leave you if they feel that her spirituality and that of the children is in danger.
Be very reasonable. Tell your wife that she's free to go to meetings whenever she wants. Drive her there. Pick her up afterward. Suggest that she might find the meetings more enjoyable if she goes on her own - children can be very distracting and often do not contribute to a parents' enjoyment of the spiritual food. Maybe she will agree to an alternate weekend arrangement, where you take the children to a museum, or the zoo, or to the park etc, while she tends to her spirituality. Then the following weekend, she gets to take them to the meeting with her. Again, you dropping them off and picking them up, as supportive as you can be.
You can also offer to do the same on week-nights, when the children should be doing homework (you will help them do it, and tidy up the kitchen while Mrs Spanner is at the meetings) and getting to bed at a reasonable hour.
Soon your children will enjoy spending time with their dad more than they do going to meetings, and will make meetings difficult for your wife to enjoy with them there. Offer to take them for an additional outing on "her" weekends so she can get the full benefit of the meetings.
Once you've got her in that routine, you can start working on getting her to miss meetings too. Get the children to tell her about all the lovely fun times she missed with the family. She will feel guilty for not joining you, and then invite her to join you sometime. Find a local restaurant that has "specials" that she will enjoy - that only happen on meeting nights.... and take her out for dinner and then shopping afterward. Do it once a month or so at first... then gradually make it an every other week event.
It does work. It's how I got hubby to stop going to meetings.
Love, Scully