pull chair, beat guard over head with chair, cut son down before he dies, and escape

There's no mention of that, you're given the option to hang your son or the guard will kill him and another. There's no mention of how. Maybe he has a gun, or he would use torture.

i assumed the guard will pull the chair from underneath your son if you don't pull it

Yeah, so....

Yes, a sadistic guard. What does assuming do?

pull the chair from underneath him implies to me that your son currently has a rope around his neck and a chair underneath him. the chair just needs to be pulled away
maybe the guard will also do some other stuff to him before he pulls the chair, but i don't see why he would go through the trouble of removing the rope

Haha. Never mind.

Yes, never mind, because at this point you look like a complete fool.

You two are going off of assumptions . . I'm going off of the text written by OP.

...I would not participate in the death of my own child and would not accept any responsibility for the guards further actions .