Tricked in to watching her autistic child

I want to star by saying I have nothing against autism and autistic individuals but my nephew is severely autistic and he’s hard to manage

My sister and I were very close until she had her son.she’s been taking care of him fir the past 14 years I know it’s not easy but it’s her responsibility

I do care for my nephew but he is incredibly destructive i invited my sister and her family over and I’m not sure what happen but within the 30 minutes for non stop screaming and me trying to assure my kids that my nephew isn’t harmful he’s just loud at some times he threw my remote at my coffee table and shattered it. I want mad but just stunned the night ended short

I have no experience with autistic people I know some are very nice but on the spectrum where my nephew is I don’t have the experience

A few days ago my family and I were getting ready to go out to eat and get ice cream. my sister called me frantic about how she need someone to watch her son she has a emergency I asked if everything is ik what’s going on she dodged the questions and said she’s gonna drop him off in a 10 mins I told my husband and he said that we can bring him it wouldn’t be a problem

So he gets here she hand me 3 bags of his things. Not 1 bag that she usually carry around but 3!!! I was confused and before I can’t even ask is everything fine and what’s going on she sped off

The night was horrible. We went out to eat and he wouldn’t sit down he threw his food in the floor many times he won’t stop screaming and he was screaming for his mother. I got so many dirty looks and I got so embarrassed that we went him the next 2 days were even worse I had to buy paper plates and plastic cutlery for him because he threw all of my plates in the floor and he even swiped at my daughter with a butter knife. He ripped the curtains off of the guest room and broke all the blinds. He peed him self. I called and called my sister I called her husband I called them so many time and left so many voice messages and they never got back to me. I was so frantic with my nephew and not hearing back from my sister or brother in law. And 11 I send one last text if I don’t get a call by 3pm I was calling the police. I called my other sister to ask if she’s heard from our sister it’s was about 20 mins to 3 and my sister tells me

Of year she’s out having drinks with her husband right now IN FUCKING VEGAS ..In Vegas

I felt so beaten down and so angry and just taken advantage of that I sat down in my garage and cried. My sister send me screenshots of her Instagram with the caption “a well deserved trip with hubs “

She called me after 4 and said oh my gosh Sandra is everything ok why did you call the police everything is fine I I just had a. Emergency to take care of I’m so sorry I never got back to you

She never one mentioned Vegas. I told her that her some is waiting for her and calmly as I can I had his bags packed clothes washed and showered waiting for her to come pick him up by the time she pulled in to my drive way I was already outside with him and his bag I put the in the back seat I put his seat belt on while his spit on me and pulled my hair. And with out a word I went back inside

Why would he’s lie to me