As per the title. It would be nice to have assistant form tutors also included in the detention notification emails. I don't see why this is not the case already. Currently only option is to ask the main form tutor to set up a forwarding email rule to the assistant form tutor.
You may also want to look at this related Idea, https://ideas.isams.com/ideas/MIS-I-597 and this one https://ideas.isams.com/ideas/MIS-I-3660