I have held 3 pets as they passed and I would not trade that moment for anything in the world. If you have the strength now or could prepare yourself before Saturday I would say from experience to be there with him. No question. He will feel your love and iit will help him to pass. Looking them in the eye, as Zero Revolt said, is a connection that can never be broken. He will go in peace and you can step forward easier. Its hard to go in but priceless and the reward is eternal.
If you cant bring yourself to be in the room then I would suggest that you have a quiet moment elsewhere while it happens and focus on nothing but Socks, even speak out to him, he will feel you with him and will not feel as though he passed alone. This is my belief.
I dont know you bro but I ,along with your friends here no doubt, will be thinking of you and him on Saturday and sending strength because I know what that moment feels like.

We come from One
In Life we sometimes forget
But, In Death we remember

Peace and Strength bro