I have a SS17 who has autism and intellectual disabilities. I've been with DH for about 5 years now. My SS functions okay in some areas - he goes to high school, showers/dresses himself, cooks a little/feeds himself - but in some areas he is really delayed and struggles - he reads and writes at about a 2nd grade level, and emotionally he's probably more like an 8-10 year old. My SS and I had a bit of a rocky start, but the last few years have been fine. He's gets on my nerves a lot - he's clingy and overly affectionate, and he can be a bit messy, but he's sweet and he just wants to be loved. We have a dog who is 14 years old and a little less than 20 pounds - I've had her since she was a puppy, and I absolutely love her to death. We all take turns walking the dog, but often my SS insists on doing it. He loves the dog and always wants to snuggle with her, and I let him even though she clearly prefers being around me. 

So here's the issue - about a week before Christmas he took the dog outside to go potty right before bedtime. I didn't even know he had gone outside with her - I was in bed with a migraine. When he was done, he brought the dog inside, came into our bedroom, and put the dog on the bed next to me where she sleeps. A few minutes later, my dog lets out a loud yelp and runs into my arms, and she's shaking really bad. She had gotten her anal glands expressed earlier that day and sometimes that irritates her, but I've never seen her in this much discomfort before. So after trying to take her back outside (thinking maybe she just needed to potty), I tried giving her a pain pill that her vet prescribed and she refused it. We ended up taking her to the emergency vet because we knew something was very wrong with her but had no idea what it was. They found nothing, changed her pain meds to one that was more for arthritic pain, and sent us home. I made an appointment with our regular vet for four days later. Our vet does chiropractic too and I was hopeful she just needed a little adjustment in her back or something. Well, the next few days (of course it was over the weekend so no access to the vet without going back to the emergency vet) were pretty miserable. My dog was clearly in a lot of pain and I was literally carrying her outside to potty, and she would just shake uncontrollably. When we asked my SS if anything had happened, he acted a little weird but said nothing. I felt like maybe he wasn't telling us something, but I wasn't sure. I asked him several more times over the next few days if there was anything he wasn't telling us - something just felt so off about the situation - and I made sure to emphasize that we really needed to know what had happened to her because it would help the vet make her feel better, but he just kept insisting he had no idea what was wrong with her.

So four days went by and our vet ended up canceling the appointment because she was sick, so we took her to a different emergency vet. Luckily that vet decided to do a CT scan of her chest - they said they were looking for signs of cancer. Instead, they found she had four broken ribs! I felt so sick to my stomach. I asked the vet if a dog falling off the bed or something similar could cause this, and she said no, this would be more like what we'd see if she'd been in a car accident - so falling even a few feet onto the floor wouldn't be enough force. So at that point I knew my SS wasn't telling the whole truth. I confronted him and told him he had to tell me what had really happened. It took probably 20 minutes of me basically hounding him until he finally admitted that she fell down when he took her outside. Still didn't add up. So I asked if he hurt her on purpose. That's when he broke down balling and told me he had gotten frustrated with her because she wouldn't go potty for him and he threw her down on the ground. I have never been so angry and hurt and just absolutely disgusted with anyone in my entire life. I told my DH what had happened and said there's no way I can be around him (we were leaving that day to go out of state to visit family for Christmas and SS was set to come with us). He agreed with me that he shouldn't come on the trip with us. I called his BM and told her what he had admitted and let her know I'd be dropping her son off at her house. We have security cameras that face the yard where he had her. After he told me that this had happend outside (the whole time we had been assuming that if anything had happened, it happened in his bedroom - it never occurred to us to watch the security camera footage until he finally came clean), my DH and I watched the footage and saw him pick her up, and then it looked like he basically just tossed her onto the ground really hard, like a body slam from a couple feet off the ground.

I know he has autism. I know he is basically more like an 8 year old than a 17 year old. And I also know that while he meant to take his anger out on her, I truly don't think he intended to physcially injur her like that. And he's expressed remorse - he definitely feels terrible. But I can't get over this. I was filled with absolute rage for weeks after this happened. Every time I think I'm starting to forgive him, I remember that he actively lied to me for 5 days while watching me worry over her and carrying her outside to go potty. He heard us talking about how worried we were. I layed on my bedroom floor and cried the morning before we took her to the second emergency vet because I was worried we might have to put her down because something must be terribly wrong and I wasn't sure they'd be able to fix it. A couple days ago, my SS made a much smaller mistake, but he tried to hide what he had done, and I got so angry with him I yelled at him and even slammed my first down on his dresser (he was standing all the way across the room from me, so I wasn't trying to threaten him, but I know it startled him). It just reminded me of him lying to me about hurting the dog, and I lost it! My DH has been absolutely supportive. SS is in therapy, has been for years, and we had a session with his therapist setting new rules around no longer spending time with the dog - he agreed and has followed these rules so far.

He's actually a good kid, but sometimes I absolutely want nothing to do with him. It's always been hard to enjoy having him around all the time because he has annoying habits and is constantly accidentally breaking things, but now I just have moments where I despise him. I also have moments when I feel more neutral. But how do I get past this? It was such an awful thing to do and I feel so betrayed that he lied when he knew she was in danger. I just keep going back to he cared more about protecting himself than the dog that he supposedly loves, and he had no regard for my feelings. All he cared about was staying out of trouble. I don't know where to go from here. I think part of the problem is because he has autism he really can't even give me a satisfying apology. He can't fully understand what he did or how much he hurt me.