How much trouble can my family get into for protecting me and my company if the invader was seriously injured or even dies?

They were protecting you and that is a claim that is just like self defense. As long as the force is reasonable under the circumstances then it is a complete defense.

I don't think your family members have to worry about getting into trouble. If the police believed that they committed a crime, they would have been arrested at the same time the father was arrested.

If he was assaulted in your home, and it was self defense or defense of others. Having said that, if your family and friends went beyond what was necessary to render him harmless, and decided to use this as an excuse to simply beat him silly, and even kill him, thenm the question becomes, was the force used against this person more than was reasonably necessary. If that is the case, then they could be in trouble.

It appears that you acted in self defense and defense of others. If so, this would be a complete defense to your actions.

I don't think you or your family are in any trouble at all, on the facts you have given stated. I don't know if you are concerned about whether or not he survived the incident; that might be something to speak to a lawyer about. A homeowner is entitled to use reasonable force to protect his/her property, and to act in self defense. If your son was the subject of an attack during the course of a burglary (breaking into your residence), and there was a reasonable probability that he could suffer serious bodily injury or death, then you would be entitled to use sufficient force to repel the invasion, and the attack. Again, I do no think you have anything to worry about under these facts.

Based on your facts I do not foresee any criminal trouble for your guests for protecting and defending persons from assault.