theres many ways to do it, the method i used was to get a reference to the ai. or rather i was lazy and referenced every actor of the ai class with the get all of class.
you could also use things like a public variable, overlaps, traces, etc to get a reference that you can then save to a variable. then you just need to make sure you identify the class via a cast for example so that you can get the functionality (events) in that specific class.
theres a really good video about blueprint communication on the unreal engine youtube channel. the video covers this kind of thing if i remember right. in any case its worth the watch.