<human>: Forgot to add it in the title: I'm a 20m

Okay, so since this is summer I have nowhere else to go besides "back home"... I'm, literally, patiently waiting for school to start so I can leave this giant shit hole and be away from some of the worst, most malicious people I've ever met: my "family". 

My father won't leave me alone because he's trying to reestablish a relationship after years of verbal and physical abuse. I, however, want nothing to do with him and am just waiting to finish school so the rest of my life can begin anew. 

-The Situation-

He just showed up to my apartment unannounced, sat here for two hours while watching a movie, and just left because I didn't interact with him (was in other room). 

I have two questions: how can I get him to leave me alone? Should I just bluntly ask "why are you here? I don't need/want you to be here, why do you insist on coming?"

Secondly: reddit, do you think a formerly abusive parent deserves to be forgiven? Keep in mind the only reason the abuse stopped was because I completely lost contact for two years (since college) because I was across the nation. However, now that I, essentially, need a place to live... I've had to resort to talking to him again. 

What do you think?

Summarize the given text in a few sentences.
<bot>: abusive father wants to reestablish relationship, I don't know if it's worth it/he's deserving, etc.