I wouldn't be so sure of it. Or even if he did, he might have thicker walls in place than Chisaki. I reckon Tsumugu might be the most anti-family person in this show, despite having shared some words of wisdom with the others in the past. There must be something very wrong with his own parents, making him doubt relationships, and no matter how you look at it, the old geezer isn't any warm and fuzzy person either but a tough old bone. Tsumugu might keep refusing any relationships for himself. He has been a distant person for all of the show. Chisaki is super hesitant on her best days, broody on her normal ones, so even if Hikari reappearring in his old brat form now somehow makes Chisaki give up for good, it's a bit hard to see how she would ever approach Tsumugu and win over his frozen heart for real. Otherwise it would be a cold and painful, loveless relationship between them. After five years of suffering, I don't really hope such a fate for Chisaki.