Aitah for choosing not to respond to my father?

So my father was out of my (28f) life for 15 years came around after i had my son. My mother and other family members told me he is a pathological liar and back then i didn't believe them (because of other lies they told me). His ex wife who ill call Ella for this story called me one night telling me that he told her a bunch of things over marriage and she didn't know if it was true.

What he told her: He raised me my entire life. At somepoint while pregnant i live in California and thats why i texted her using a California number My mom was on substances. That my son and my little brother (same age) visited and played all the time. He also showed her a picture of a light skinned girl who wasn't me and claimed it was me.

The truth: He was never around and never tried to be. Ive never moved out of NC. My mom was disabled she only took what she was prescribed. My son and my little brother have never met.. ive never met my little brother.

I told Ella all of this and then had issues where i had to parent my own father on a phone call after he was fighting with her and he snatched her phone away from her. Blocking me on her fb and not realizing we were still connected on insta. Cops were called..

I blocked him for a year when this happened..

Next wife who i will call Millie. We met while i met up with my father for dinner one night. Millie and i went to the bathroom as soon as we got there and i told her straight up that if she ever didn't know if he was telling the truth about something she could ask me and i will do my best to give her the most honest answer i have.

At some point the two of them separated for a while and she wanted to see other people.. he set her house and car on fire. We believe that he might have been trying to kidnap her and i days before this and did that as a result of not being believed that he had stage 4 Leukemia but him saying to go to a doctors appointment with him. He could never show me proof or paper work without the paper work being cropped in a weird way like paper turned diagonally cutting off a lot of information. I asked Ella about this she said when they were married she went to doctors appointment with my father. He never had cancer. He tried to say that that was a reason why Ella left him.

I told him one day to tell me the truth or show proof or i was gonna show everyone all my evidence as to his claim for cancer. Gave him 24 hours. After 24 hours i posted all my screenshots from Ella, Millie (of course blocking out their names)and my father. He tried to threaten me and guilt tripped me when that didn't work to take it down. Was calling my kid by the wrong name and ive corrected multiple times in the past.. which made me go off. He blocked me after.

I found out he slept with another woman the night before Millie and his wedding day. That lady also showed up at the wedding. (The lady messaged me with receipts)

A year later and i see him in my suggested friends list.. then today he sends me a message saying hi..

I don't know what i even could say to him at this point "Hi" back? A "how have ya been?" I can't. I don't want him around honestly.. but hes my father.. im conflicted..