Autism Doesn't Matter!

I was very excited to be a maid of honor in an upcoming wedding. The dress is currently being altered by a professional seamstress. Hundreds of dollars were spent on the bachelorette party and bridal shower. The personalized gift has been purchased. Plans continued to be made for a third 10 hour drive with our three children, now ages 5, 4, and 14 months.
A week ago I received a text from the bride-to-be stating that the rehearsal and dinner are on Sept 30. GREAT! I already have a dress that will be appropriate! Maybe I should order cute bride and groom tshirts? Oh... I'll have to see if it's in my budget and if it could arrive at my parents home in time.
My return text: who from my immediate family is included?
Just you and your husband.
Oh no... my heart is in my throat. What will I do with my 5 year old who has autism, my 4 year old who has issues being left places since preschool started a few weeks ago, and my 14 month old who has reflux that causes her to stop breathing???
For every out of town rehearsal, we have all been including in the dinner even if we weren't in the wedding. I hadn't considered this being an issue.
I am told by the bride that there is a list of babysitters I can call and they can watch the children. However, we are arriving the day before and I can't see how this will work for us. I have to tell the bride that we can't attend the dinner but I will be at all of the other events.
The bride now calls me on the phone and yells at me - I need you at the dinner. We have suprises planned that evening. This is all about me for a couple hours. AUTISM DOESN'T MATTER FOR A COUPLE HOURS!
I remain calm but thankfully the bride hangs up on me or her phone cuts out. Either way, I am left with that comment. Autism doesn't matter for a couple hours.
I digest this comment. It is clear to me that the bride has not taken one moment to realize that autism does matter. It matters every minute of my son's life. Kids with autism lack empathy, common sense and that inner voice of alerting them from right/wrong, dangerous etc. Not one moment can be taken for granted or assumed that your child with autism is making right choices. He has safety measures in place at school and at home. If I don't keep him safe all of those minutes, I will never be able to take it back or replace him. Yes, EVERY one of those 60 minutes in one hour I am worried about my son's safety. I can't turn autism off any one of those minutes.
This past Monday I was kicked out of the wedding. I was kicked out of a wedding because my son has autism. The sickening part of the story is that the bride is my sister. My son's only maternal aunt.