"People grow apart. You are very different." Mostly he's thinking that by all accounts, Dante was a giant jerk that over-compensated for not having his brother's intelligence by making him feel inferior in spite of being the opposite, but that's clearly not something he'd share. Not right now and likely not ever. It doesn't matter anyway. None of that makes them not be brothers, none of that means that Dante didn't care for Cisco. Obviously it doesn't mean that Cisco doesn't care for him. "There's still good memories, right? Family."