My father owns a shop he tells us about his business and carelessness of his workers at home. Is it haram for him to do so? And is it haram us discussing about it at home? I mean he is telling us about his workers is it wrong?
Here's the definition of backbiting the Prophet gave:
Abu Huraira reported Allah's Messenger (ﷺ) as saying: Do you know what is backbiting? They (the Companions) said: Allah and His Messenger know best. Thereupon he (the Holy Prophet) said: Backbiting implies your talking about your brother in a manner which he does not like. It was said to him: What is your opinion about this that if I actually find (that failing) in my brother which I made a mention of? He said: If (that failing) is actually found (in him) what you assert, you in fact backbited him, and if that is not in him it is a slander. -- Sahih Muslim 2589 (sunnah.com)
Asking the question implies the employees would not like this conversation. If you can work out exactly who the discussion is about, it matches this definition, and can be regarded as backbiting (or sufficiently close to backbiting to stay away from it).
However, it wouldn't be backbiting if the employees are sufficiently anonymous:
If there is no danger of anyone figuring out who is being spoken about, and if there is a genuine benefit from relating the matter – like setting an example or conveying to people a valuable lesson, then it is permissible. -- Islam Today