We all have to face it that the best decision is to have Yui back to his papa. The dad beg...

look you are right, but I'm going to downvote you anyway.

I’M CRYING WHY WAS THIS SO FUNNY

hahahaha yea i love petty people. is cute

I just don't agree with this. Saying that Yui's dad taking back custody is the best decision is kind of tone deaf imo because what about Yui's feelings..? Her father is her father biologically, sure, but that doesn't mean much, especially when he's essentially just abandoned her for years with the excuse of "I can't provide her a worry free life" as if that makes up for offloading a child onto your brother in law(?). It should be up to Yui in the end and deciding that the father is the best choice because he's been working for it is just so... Wrong. I don't think Jiu wants Yui to forget about her dad, I think it's more that he can't trust her dad to take care of her since he failed to step up when she needed him the most. Especially if he wants custody of her to bring her to America that would be uprooting her to an insane degree and it'd be hard imo to justify it

I wanna add stuff to the discussion here.
Yui mom and dad divorced before her death. With implications how the mom was taking care of Yui mainly I feel. From the first volume of the manga there is other mention of this dad figure too, dad has literally no contact(not calling, not facetimes, not even sending letter/postcards) with Yui.
There is the lines of how Jiu updates the dad about Yui's life with very minimum details though that adds to the dad's case, but I wanna be hopeful that Jiu has some reason at all for the hostility towards the dad(probably insider knowledgeof the divorce Yui can't understand, my delusions). Then Jiu also mentions that dad had come begging him to take in Yui since he couldn't afford it, which is something I dislike but somewhat can understand. However this I believe is countred with Jiu to take care of his niece, had to quit his own job and change his entire path in life(does starting your own business being a detective for hire seem lucrative, got to be something to afford a live-in housekeeper though). This dad shifted the responsibility of caring for his child onto someone else, a someone else who was in no place to even care for a young child grieving the loss of thier mother. This absolutely had impacts on Yui who has abandonment issues(bro she just wished everyone was together ;-;). I would not trust this dad with sole custody and to take Yui across the world in an environment that is entirely unfamiliar in the culture and language.
Also for a side note there's the human vs beastman differences to deal with.

The thing is tho is that her dad DID abandon her.

He left her alone during the passing of her mother and basically relinquished all responsibility onto his brother-in-law just 'cause he "felt" like he couldn't raise his own child. He didn't even *attempt* to take care of her before dumping her onto another family member. Jiu probably doesn't think the father is mature enough to even take care or himself, let alone a child, which is why he keeps the updates to a minimum. He's a beastman that wants nothing but the best for the child he's been raising like his own. The child his beloved sister left behind.

From what I gather the dad has never even sent any sort of help over to Jiu to raise Yui. He's been doing it on his own till Kaisei came into their lives. Food, clothing, shelter and even a caretaker for when his job takes him away from the office-- that has all been solely provided by Jiu.

You can't expect people to be OK with a random person-- even if he is her father-- just showing up out of the blue to uproot 3 people who have formed their own familial bond with each other.

And as a child who had to spend their life being handed off back and forth between households I often wish-- even as a 31 yo now-- that someone had had the kindness in their heart to permanently take me in and give me the stability I needed. Instead, all my memories are full of having to pack my shit and move across state every year or two 'cause my parents couldn't get their shit together.

Whose to say that Yui's father won't do the same if his lil business in America fails and he "feels" like he can't raise her anymore. She's already got a stable home with Jiu and Kaisei and she loves them both very dearly and wants the 3 of them to stay together. Uprooting her from the people she knows just to take her halfway across the world would only hurt her in the long run.