i also refuse to not vote my conscience but i figured this time its not like doing this abstract process to pick if id prefer -100 points vs -200 points is gonna matter that much if i genuinely believe itll even be slightly better under kamala i might as well

Not calling your buddy Ben Shapiro, but that's a Shapiro-esque sentence. Throw out as much shit as you can is as short a time as possible so that any response would basically have to be novel length.

• He says he will not vote for his conscience, yet he votes for someone he clearly views as bad.
• He says the process is not abstract, then makes abstractions.
• He says he believes things will be slightly better under Kamala (not incorrect, it's his belief. It is the belief that is wrong here. Things will not be better under Kamala)
  a. going into the third point requires a lot of work, and I can imagine you've already talked a lot about that particular topic, so that's also just shitty of him to disregard whatever you've said like that.
• Unrelated to the sentence, but if he is defeatist then he should view Trump as the better of the two candidates, considering the fact that he is currently experiencing the system under Kamala-lite (if he believes what she says, she is basically campaigning on being a more right-wing Joe Biden)

I personally would focus on how voting for better domestic policies will do nothing but make things worse. The extermination machine will not stop in Gaza, it will come home. There will be no better domestic policies. I would focus on the massive resistance towards all the things the dems are doing, that Trump couldn't do because he was either incompetent or because the general populace exerted enough pressure to stop it.
Trump pardoned a sheriff and even that was a massive scandal (as it should be, but let's not pretend people would have given a shit under Biden.)

edit: on the bright side you get to give your friend the experience every leftist dreams of: Living in a world were they are considered reactionairy