I'm not sure how the cops work in cases like these, but I think this would at least be a "disturbing the peace" issue. I can see how one might have reservations about calling them, though. They'd probably tell the husband to settle down, and he might've quieted down in public, only to save all his pent up anger for his family in private.

Alternatively, you could've distracted the husband, and then slipped the wife a number for a DV shelter. Then she would have the chance to get herself and the kids and the dog to safety before the cops were called.