Autism and playdates

So B (also known as capatin A) is having a friend to play today! This friend was meant to play 2 weeks ago on a thursday and we were all geared up house spotless I had made ginger ninja's (B's fav snack) and the whole house was a buzz. Got to school went to the friends mum to make sure she remembered where she was going to get to our house and she looks at me confused for a minute and says "oh I have some work to do so we can't make it today because I want the boys with me" (she is a teacher at school art and prep). Most kids would be happy with a re scheduled play date. B was at his worst and nothing would bring him back to earth. I am so greatful to my bestie who was able to help get the 3 littlies into the car while I was wrestling with B to get in and stay in. He was kicking windows doors seats throwing anything he could grab then opened the door and tried to run infront of a car! Scary :( All this resulted in a day off on the friday because he was still melting down over it at 11pm. Last friday the mother asked if they could come for a play today (she wants to be here with him) as her oldest has a play with a friend this arvo too! So I said yes! Wasn't planning on telling B till today when I knew for sure but he over heard her say it so we have been on the countdown to when L can come to play. I am nervous about school drop off today worried that we will get there and she will cancel on us again! Have even discussed with bestie on what I will say if she does cancel again. I will tell her (nicely) that while it is great the boys are good friends I think we should leave playdates to a spur of the moment thing as B can't cope with change of plans and not being told till last minute. Fair??? I think so because i don't want any bruises today! Wish us luck it's going to be a long day i think!