I can see that your concerns are valid, but they seem more hypothetical, in this context. Since I’m not mean or clever enough to create a meme that would go viral, maybe I’m being naive here, but there didn’t seem to be anything in the video to deride, that would be “worthy” of a meme. I could see this video being shared on Reddit, where someone there could potentially do something like that (or is that more like 4chan territory?).
As for strangers wanting to help the kid, why would they do that? He seems well-taken care of. Do people actually try to take selfies with autistic people? I would think that because of the public perception of autism, they’d be afraid or concerned that an autistic might scream or shriek, as we’ve seen in movies. They made this little video so we could see an autistic kid who was calm and capable of having a coherent conversation. I’m sure a lot of people wonder what an autistic is capable of understanding, and this video gave us a little glimpse of one individual. It was like an informal case study, and not at all exploitative. Also, I’d infer that the son and dad had a talk beforehand about the video being posted to the internet for anyone to see, so there probably WAS informed consent.