Tragic to read what you post. There is a perfect solution here, that you seem to have missed totally. The guy was already attacked and brought to the ground. He was trying to crawl away. The property owner could have held him and called the police to remove and charge him. Instead, he made the choice to kick a man already laying on the ground. You don´t need to talk about getting away scott free. The point is that the owner had already diffused the situation before he caused grivious bodily harm on a person seemingly unable to defend himself. So, he used violence, when there was no need for it.
That he attacked him from start is not anything wrong with, as that is defending his own property. However, adding extra violence that can be tracked down as a reason for a person´s death can never be right.