GetShouldHelp
As of Skyrim 1.8.151, this condition function is not used in Skyrim or any of its official plug-ins. Because of this, this function's intended purpose or functionality is unknown.
More testing is needed, but it seems that this condition function returns 1 if the subject actor would assist the target actor in a fight they weren't otherwise involved in. For example, assaulting an actor's spouse may cause that actor to become hostile too. In that case, a GetShouldHelp condition between the spouses would return 1. This heuristic does not account for actors that become hostile upon witnessing a crime, like a guard.