Ok, the very first idea of this fic has a lot of promise, but the way you developed this story is horrible.
1.Grammar, I understand some mistakes can easily sneak by in a sentence, and I'm not a grammar nazi that expects everyone to have Shakespearean levels of writing expertise, but you make a lot of mistakes multiple times with the same words, it feels rushed, as if you were either so excited to write or bored as hell and wanted to finish the chapters and be done with it for the day.
2.Pace, dude calm down, describe your character with more details in his old and new life, try and give more life to the environment and the people in it, there is no need to create a backstory to every single being you imagine during the story, but have interactions between characters that display their personalities or further the plot.
3.Character, he was a 37 year old, Doctor, and was an overall good person....ok.... then why does he seem so empty? like, no motivation to really explain the reason for choosing Broly( even though it's kinda obvious) and DC, and with all this knowledge of DBZ, DC, medical science and equipment he acts like the average wannabe saiyan warrior but
there is nothing in his life that made it logical for him to act like this.
His interactions are either non existing or forced to the extreme, everyone simply accepts his actions because of plot and even though he could make something like Flash's calorie bar to make it seem like he eats like a normal person, no let's just pack a tank sized meal for everyone to see.
I get that this is fanfiction and the existing logic in the universe follows the author's wish and plot but you didn't do a good job, trying to force everything without any logical explanation, things are always happening around the world that the MC is not a part of, you don't need to exactly keep track of everything, but you need a small notion of timing to integrate everything together, or else like the BatmanVSuperman you will make a lot plot holes and keep digging more a the story progresses because everything that happens, simply does, so there is no progress being told, no evolution or development.