wishing, It sounds to me like he's trying to control the situation by stating he wants you to cancel the appointment and any further appointments are to be run by him. I would not cancel the appointmnent. However, I would discuss with the counselor about having a father/son session and see what the counselor says.
Sometimes mlcers see things in a different light, but he could very well be thinking that if your son can't be around the ow, then he can't be around a counselor. Your h could also be afraid of what your son may tell the counselor...but who knows what is going on in his mind these days.
I would be very surprised if the appointment gets cancelled.
BTW, I'm glad you stood your ground about your son being around the ow.
I hope that you are doing something fun this weekend.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.