Ukraine actually does, on the condition that the rest of Ukraine agrees to it as well. While I'm not aware of the right being explicit anywhere, the right to self determination (meaning secession) for peoples in Europe and Asia has been a liberal (and left) position for over a century, and it should be easy to demonstrate hypocrisy and opportunism when say, Taiwan should be allowed to secede but not Crimea. If op's "bro" is so nakedly reactionary that they don't care then op should simply use that metric to end the discussion.
Ukraine actually does, on the condition that the rest of Ukraine agrees to it as well. While I'm not aware of the right being explicit anywhere, the right to self determination (meaning secession) for peoples in Europe and Asia has been a liberal (and left) position for over a century, and it should be easy to demonstrate hypocrisy and opportunism when say, Taiwan should be allowed to secede but not Crimea. If op's "bro" is so nakedly reactionary that they don't care then op should simply use that metric to end the discussion.