My dad is accusing me of wrong doings on a daily basis when I've done nothing. Any advice?

Did your Dad provide for you and love you when you were growing up? If he was there for you in your younger years, even though his accusations hurt really bad and make you angry, try doing your best to deal with him now. Maybe spending less time with him would help.

I do the most for my mom yet I’m the one she gets angry at and I’m the one who gets no birthday or Christmas presents. I tell myself at least when she’s gone, I’ll have nothing to feel guilty over or regret.

who is taking care of dad 24/7 ?

Yes, his accusing is part of his dementia...its hard but imagine how hard his world is now,