Honestly, I hate being this negative, but this is just bad writing. There was absolutely no foreshadowing about this, Kano just randomly thought 'oh right I've always been worried about my dad by the way' in the middle of figurative nowhere, and surprise he appears in the next chapter. It's obvious the author threw this in as a way to drag the plot along, they probably think once they resolve the central conflict the manga is over, so they're desperately trying to stall it in any way possible. It's just... lazy. It's incredibly lazy. They've created a character with the sole intent of grinding the story to a halt. Again. He serves literally no other purpose here. It's possible they drew the plot element out of a hat, along with 'character has to move away', 'another love interest beats main character to confession', and 'bullying at school'. At no point do any of these change the story, only move the goalpost another hundred yards away, over and over, perpetually avoiding the ending like a bad soap opera.
This manga needs a goddamn writer, because this story is 90% length-padding and 10% actual content. I know we're all on the same page, but it consistently baffles me that published manga can be this formulaic.