To me it really doesn't matter if he pulled a trigger or not. If he was there and he did not stop it in the planning stage or execution stage he is just as guilty of 8 counts of aggravated murder as the others.
Keep in mind CO these people planned this for four months at least. That means George had plenty of time to make a call, even if it was an anonymous call to LE and tell them his family was planning on slaughtering another entire family over custody of a child.
Now think about yourself and your own family. If you, God forbid, ever heard your family planning to slaughter an entire family, would you make that call to LE? I have a feeling you would as would everyone else on here. And that right there is the difference between good, honest people and evil to the core, mask wearing "Avengers".
So to me whether George stayed home and watched the kids, or whether George was present, whether he fired a shot, or just stood there looking stupid and watched, he is every bit as guilty as his father, mother and brother. That also goes for any of his other family that may or may not have known about the murders before or after.
Please everyone remember those interviews with Gary's dad, Miss Geneva and Lenny where they struggled to hold back the sobs of pain and grief when they talked about their dead children. They are the real victims here that are still living with the pain, grief and horror of that night. I bet not one of them would try to downplay George's role in the killings or have one shred of sympathy for any one of the W4. Just like I do not now, nor will I ever have one shred of sympathy for any of the W4, no matter what their life was like before. And I am sure as the sun rises in the East that all 4 of them are guilty as sin.
JMO