I think my dad has early onset alzheimers
Why do you think he has Alzheimer's?
I read about it on the internet and I really want to hurt my Dad by telling him he has early onset of alzheimers
It is understandable that sometimes we want to hurt our parents when they hurt us but lying about something so serious is wrong. You should care more about your elderly parents. They need the help and it is the responsible thing to do.
I think, because of the way he treats me and because he tells me to be strong all the time, I would treat him like shit.
What your father is doing to you is wrong, but if you lie to him and say that he has Alzheimer's, it's going to be very damaging for him and I do not think you will be forgiven with that. Try to just talk about how he treats you and see if he could try to be better, instead of retaliating.