It has been interesting over the years of ministry with adults with intellectual disabilities, that there have been several occasions, only a few, where those with higher functioning disabilities have manipulated those with a bit less intellectual abilities.
One happened about 10 years back when two women got into a sequence of altercations. The higher functioning woman seemed to instigate the confrontations. Because she had a better command of language, she would typically frustrate the other. This happened repeatedly until ultimately the woman with less command of language in frustration pushed her such that she fell down. The result was the the first woman called the police, filed an assault charge and basically scared the other half to death. I would reassure her that nothing would happen as a result and nothing did, but it forever scarred the less capable woman and she never returned to our ministry the other for a while would show up with her Cheshire cat grin.
Most recently, a similar situation occurred between two women and a man in our group. The women being the higher functioning and the man less so. We ultimately came to understand how the two had been manipulating the man. I spoke to him on several occasions trying to explain to him what was happening to him and also spoke to one of the women telling her to stop the behaviors she was engaging in. But she continued and her manipulation was too powerful for him. Ultimately it set him off to where he became mildly physically aggressive but it might have been much worse. As it stands, all three of the group are not involved in our ministry. The man through input from his family has separated himself from our ministry, probably a wise move on his part, and the women were asked to leave for a period of time. I plan to continue to facilitate friendship with the man. Hopefully they will follow our request to refrain from the social media interactions and posts that led to the altercation.
The take home lesson is that people are people and will often do the kinds of things people will do. Particularly if the see that they have some power over others. If you are aware, try to protect those in your group who might seem more competent than they are and can be bullied by others. I was grateful that the altercation didn't escalate more than it did.