Few Things:
1) Ameri knows Iruma is human. There is literally no doubt in her mind, but she doesn't report on because she loves Iruma. It started out as guessing on Iruma's nature then her making an excuse for Iruma to read her books to just flat out waiting for Iruma to tell her. She basically is just waiting to hear it at this point.
2) Iruma is severely traumatized by their time in the human world. Ultimately what I would love is Iruma to actually freak out and not be able to talk because they don't know what to do. Ameri can then hold them and say it's okay and Iruma reveals the truth.
3) At most I think we will get an Ameri meets her mom arc going on here, possibly even meeting the mangaka that writes her favorite books. Regardless I don't see Iruma meeting their parents ON PURPOSE.
4) I think this will end on Sullivan saving them and being questioned by border patrol and giving Iruma a ticking time bomb of having the whole nether world find out they are human.
5) I kinda think this will be the proper point to start heading toward the ending of the series. Not quite Elbaf, but like Marine Ford, you know?