[hocus pocus]

As it's been said, the denial could allow this person to carry on as normal. Additionally, people who harm others don't always see what they've done as wrong because they are ill. So it's possible he doesn't see or understand what he did to you as wrong and is continuing to live his life like nothing happened.

I'm sorry to hear about your mom's reaction. It takes a lot of courage to tell someone about what you've been through and being disregarded like that is damaging. However, as someone has said, don't let your mom's reaction keep you from telling other people about your experiences. There are many reasons as to why your mom could have reacted the way she did, but not everyone will have the same reaction. I think you should consider telling someone about this so you can get it out of your system and have the support you deserve.

School administration does usually call your parents in a situation like this, however, you're eighteen, so they shouldn't have to. You can remind them of that to see if that keeps them from calling your mom. You can also explain that your abuse is in the past so they're less likely to report, and you can tell them that your mom will only hinder your health and recovery. I know some schools do not call home if parents are part of the issue or if they're too negative.