In the unlikely best case, they get the case dismissed, but even in the most likely case that the motion is denied, they win by wearing down their opponent who has much more limited resources and is personally affected by the case dragging out, i.e. more likely to accept a (lower) settlement than without this tactic. The only downside is a tiny bit of legal costs.
Courts should be able to issue sanctions/extra damages for the use of such tactics. If using such a tactic turned the claim from "you killed this person negligently" to "you killed this person negligently, then willfully tried sleazy tricks to create additional suffering for the husband", and had the potential to double the award, companies would be much less eager to play this game.