Why does it have to be the way it is? (Soukoku)

Dazai bought Yumeno to his house after his treatment.He wanted to keep Q safe and felt guilty that he left Q in pm alone, he was abused by Mori, he thanked the all mighty that Q wasn't sexually harassed. The ada understood the child's condition and were working on that matter. Kyouka and Kenji started talking to Q as they would have breakfast at dazai's house soon the three became really good friends. Chuuya also understood his situation and it wasn't difficult for him to bond with kids. Dazai and Chuuya were like parents for Q. Dazai took care of Q which was very different and sweet for a pm kid but that was the thing he longed for, someone to care, someone to love him and someone who could call as his family.

During a mission Kunikida found a girl ,she had bomb , it was an attack planned against them. Kunikida somehow saved the little girl and bought her to the office.( Basically cannibalism arc but Chuuya is not fully against ada as they are like family but have to follow the orders that ada understood, same applies to Kouyou. And later Akutagawa and atsushi put an end with Dazai's help) . After all the mess the ada found the girl was an orphan and her name was Aya.

Aya - I don't know anything about the bomb, sorry.

Kunikida - you don't have to be we are glad that you are safe.

Dazai - can I know your name and anything about where you live so we can help you child. Said with a warm and soft tone.

Aya -  My name is Aya,I am an orphan I don't have anyone, said looking down eyes filled with tears.

Dazai - I am sorry I didn't know Aya,but.. he looked towards the president with pleading eyes. The president understood his motive afterall the ada is nothing but an organisation adopting people of any age.

President - You can stay here if you want to child.

Aya- I can be with the ada, asked as she was suprised by the offer.

Dazai - of course, would you like to stay at my house. I already have a kid in my house as other ada dorms are full. And most of the time all the kids would be in my house.

Aya - I would like to be with you sir.

Dazai - oh, no need to be formal my name is Dazai Osamu.

Aya- okay Dazai -san.

Yosano - Dazai, you be collecting kids like  Pokemon card.

Everyone laughed at her comment and went to their home as it was getting late.

After few days Q and Aya were like siblings and Dazai was like their mom, all the ada kids were happy. Both Q and Aya would spend their time in ada with others, they were sweet towards the kids and at home dazai would pour his love and affection and treat the kids as his own, he basically adopted those kids.

Chuuya and Dazai were on good terms , but still Dazai was hesitant to accept him fully, he was afraid of losing him . His heart can't bear it. Just the thought of losing him makes him soo sad.It is taking him some time to comprehend his thoughts.And Chuuya knew why Dazai is still taking time.

For some reason Q and Aya were really like Chuuya and Dazai's kids . Physically Aya was like Chuuya in many aspects her facial features, her lavish ginger hair, those ocean blue eyes, and not to mention her stubbornness, temper and height all matched perfectly with Chuuya ,while Q's behaviour is so much like Dazai he is lonely but wouldn't ask for help, mysterious, charming, cunning, sweet, dangerous but would do anything to save their loved ones and if you know well they both longed to actually just love them, have a family.

Both the kids very well knew about Dazai and Chuuya's relationship, it was complicated but the kids know how much they loved each other. They just wished their two parental figures get married and lead a happy life.