My 24M dad 49M is marrying the woman who he forced to get an abortion. Does anyone have any advice on how to talk to my dad about it? Should I even?

Just for a little context my mum 48F and my dad 49M divorced when I was 11. I ended up living with my mum and she told me all the things he did leading up to the divorce like cheating, neglect, drinking and doing drugs. He even sold my Nintendo DS2 for booze. Over the years he got better as a father and has been sober for almost a decade now and I'm proud of him. I tolerated all the short lived girlfriends he had because I wanted to support him which now comes to the current situation.

He met this woman June 45F (name hidden for privacy) and hit it off, they got close and eventually they proposed to each other and are waiting for her divorce proceedings to finish so they can get married. My dad worked so very hot to clean up and get fit and he looks amazing now so, when I met June a couple weeks ago, I did my best to make a good impression. We went out with, my dad me and her, and talked and it was a good time. My mum hasn't been in the best of places since family deaths a few years ago hit her nude and she's been revealing to me information that I didn't know until now revolving around the divorce and their strained relationship. They always argued together and even more apart. She tells me that my dad cheated on several dozen women during the marriage and got someone pregnant and forced her to get an abortion. June.. is that woman. My dad never told me and led me to believe they had met for the first time a few months ago.

I am struggling on how to proceed forward, I don't know what to say, if anything, to my dad. I dunno if I should support this any further or confront him or even how to confront him. I've done my best to keep a good relationship with him since I rarely see him and I feel like he's done the same but now I am having an anxiety attack over this when not even the most stressful time at university would.

Thanks for reading and any advice would be much appreciated.

Edited to add a missing age and grammar