My girlfriend has autism and when I want her attention I need to ask for it like 5 times over a space of 20 seconds, if I don't ask multiple times she will literally forget I even asked in the first place. Sometimes it literally takes a minute. This isn't because she doesn't care about me, it's just how her brain works.
Maybe this is just a better form of communication for him while he's focused on work. Please don't assume ill-intent, it just seems unnecessarily rude.