Feel pretty good about him staying but if we don't agree to pony up for assistants, recruiting budget, his own salary etc. I would leave if I was him too. Like any smart negotiator he is creating leverage (you should all take notes for your own personal work situations).
I would just be very surprised at his age and with what he's accomplished that he would elect to move again and put himself into a pressure cooker job at a bottom tier P5 school, unless he really really misses the west coast. Time will tell!