Everybody needs urgent help, Sujay, we do what we can
Deleting all related entities as well, requires a bottom up approach: first delete the related entities, then the top entity, and you can do that using a unit-of-work, or methods like DataAccessAdapter.DeleteEntitiesDirectly(), or store the entities in a collection and delete them in one go, or you could enable Cascading deletes in the database you're using (on the FK constraint). you then delete the pk entity and the RDBMS deletes the rest of the related entities.
cascading deletes aren't supported in llblgen pro, because they can do great harm and it's not always possible to enforce them due to multiple paths to the same entity.