A couple laws to look at. These are from AZ statutes. Keep in mind I'm not an expert on AZ laws but the AZ statute is very similar to IL statutes and yes I am up on IL statutes.
13-409. Justification; use of physical force in law enforcement
A person is justified in threatening or using physical force against another if in making or assisting in making an arrest or detention or in preventing or assisting in preventing the escape after arrest or detention of that other person, such person uses or threatens to use physical force and all of the following exist:
1. A reasonable person would believe that such force is immediately necessary to effect the arrest or detention or prevent the escape.
2. Such person makes known the purpose of the arrest or detention or believes that it is otherwise known or cannot reasonably be made known to the person to be arrested or detained.
3. A reasonable person would believe the arrest or detention to be lawful.
And on individuals making arrests
13-3889. Method of arrest by private person
A private person when making an arrest shall inform the person to be arrested of the intention to arrest him and the cause of the arrest, unless he is then engaged in the commission of an offense, or is pursued immediately after its commission or after an escape, or flees or forcibly resists before the person making the arrest has opportunity so to inform him, or when the giving of such information will imperil the arrest.
This tells me that in AZ private persons can legally make arrests, the first law tells me that when making arrests any use of force necessary to make that arrest can be used.
Considering this guy has worked law enforcement, I'm sure he is aware of the laws.
Now show me where there is a law that says this man has to sit back and isn't allowed to take action to protect his property as long as it is done in a lawful manner. Regardless of the size of his property, be it a lot or 1 million acres, he is the owner and is afforded rights under AZ law and the US constitution.