In many places it is the law that if a law enforcement officer requests assistance from people in making an arrest that people are required to provide it. Texas provides an example of that with it written into the state legal code. Refusal to provide assistance can result in the arrest and prosecution of the refuser as well.
Vigilantism is working outside the law. Assisting an officer is; assisting a law enforcement officer in his duties.
Regardless to add. He was with his wife, who most likely was in the line of fire as well. For what? A breaking and entering? Is it that worth it?
I am not sure I understand. Is your post implying that his wife can not assist also? So far as "worth it" I can't really say. People need to make up their own mind about that.