The story is really just about the mystery of the father's disappearance, with everything else having little relevance.
You probably could have just made this a detective story with no time travelling, and it would have had little consequence on the over arching plot.
Like, what was the point of his relationship with Tomoko?
Why didn't he try capitalising on any of his 'future knowledge'?
Why didn't he try spending more time with those he knows will die soon?
Why didn't we get to see what the father was up to?
A lot of elements just don't feel quite satisfying, like with how the little sister was sad that the brother wasn't being nice to her anymore and... it's just left at that. So his relationship with her wasn't fixed, bar his time travelling back? Was there much point in ANY of the characters really, beyond the family and Daisuke? Everyone else could have seemingly been cut.
One of the conflicts of the story was the MC worrying about his wife and children, but we never really saw his relationship with them beyond a quick dream.
But despite everything, I still really quite enjoyed it. all the unresolved plot threads, and unnecessary characters, somehow feel appropriate. Like it's kind of a statement on the plot itself.
The MC couldn't stop his father leaving,
That friend would have died on his motorcycle anyway,
That guy was going to get stabbed and by a yakuza,
Tomoko was going to leave to America and thus their relationship was fated to end regardless.
You can't change the past, and we have to live with all the questions and unresolved mysteries.
The only thing we can change is the now, which is why the MC is changing his attitude with his family... though this would have more impact if he actually
HAD an established relationship with his family (from the view of the reader).
Overall, a good read that I quite enjoyed.
If you're looking for something similar, that has a bit more tooth to it, I recommend "High Position" (
https://mangadex.org/title/f59b01e3-2e05-4883-a9cd-3f718363fd04/high-position)