he'd be unlikely to want to see the gender-swapped reboot where he's turned into cucked out hermit drinking green walrus milk.
The only leverage you'd get him would be a magic cure for parkinsons.
Gosh, how would they bastardise it if they were doing a sequel now?
I think they'd scrap the future of BTTF2. Have Marty say a line about it not being the future he visited from the 80s. His kids will not believe the Time Travel stories. Thinking it's akin to his dad's sci-fi writing. Maybe Marty turned the stories into novels.
The main character would be Marty and Jennifer's daughter Marlene (Possibly be Trans due to her being plated by MJF in BTTF2). Doc Brown will be the even more brilliant daughter of Emmet Brown played by Kristin Wiig. She will have built a new Delorian. However, it's got a much sleeker, modern looking time conversion.
Once she shows up and the kids learn the stories are true. Marlene will lecture Marty on his selfish use of time travel. "You could change anything in history and just made grandpa a rich successful author?" Marty will reflect that she's right.
Female Doc Brown will have come to get Marty's help, but he sends his SJW daughter instead because she knows more than he does. He trusts her to be more responsible.
Somehow Marty and Doc Browns travels in the original films have created a change in history that always ends up in a terrible future. They must go back and fix it.
They go on a mission to find clues. Past, future, different time periods. Losing the appeal of the limited time periods of the originals. It's just a spectacle of where they are. Often showing the horrible ways white people have been.
Eventually, in one of the past time periods, Marlene meets a black woman who is oppressed. Yet is very smart, well educated and seemingly has an intuitive understanding of the technology of the time machine. They discover that no matter what white men like Marty and Doc Brown did, it'll always lead to a disaster. It's not just their actions, but the actions of white men.
The black lady asks if things get better in the future, and they tell her no. They help her start a woke revolution in the past. Where everyone has present-day woke values except the white rulers. When they return to the present day, it's a Star Trek-like future.