Peter and him never really got along, but when Tony was announced missing, T'Challa knew that whatever negative felling the child held against him that he would care for him until Tony was found. He knew that the boy would lash out, throw tantrums and maybe even kick him. He knew all of that might happen, yet he did not leave Peter out of his site, he supervised any visits that the child had with anyone, including Obadiah Stane, Virginia Potts, Harold Hogan and James Rhodes.
Peter knew he was being difficult, but he couldn't help it. His Mama was gone and nothing anyone said to him made him feel any better. The closest he had come to being comfortable was when he went to his Mama's room and slept in his bed. Cuddling T'Challa to stop the nightmares. He didn't understand why the man let him in the bed considering how difficult he's been acting, but is happy to have someone care for him.
As the months went by Peter isolated himself and only spoke to T'Challa, his Daddy. Because he remembers how Mama had always tried to get him to call T'Challa that. He regrets not doing it sooner. He misses his Mama, but Daddy makes sure that he never feels alone, and sings him to sleep like Mama used to, though his voice isn't as good. He likes that Daddy understands what he's going through with Mama missing, because it means that he doesn't have to act brave and strong like the others want him to.
When Mama comes back, he's hurt but he's home so he and Daddy hold him and promise to keep him safe as he falls asleep. When Mama wakes up the next day and shows him and Daddy his arc reactor Daddy cries and tells Mama that he's sorry he has to suffer like this. Peter is happy that it keeps his Mama alive.
He and Daddy had gone to buy pizza when they catch Obadiah trying to steal Mama's Arc Reactor. Daddy beats him until all you can see on his face is blood. It's gross, but he tried to hurt Mama so he deserved it.
It takes months for Tony to heal and T'Challa is there with him all the way. Even when his husband reveals to him and Peter that he as Iron Man they supported him, they help keep it a secret. When T'Chaka connects the dots, he immediately asks T'Challa to become the Black Panther. To protect his son and husband. As his father is still king and a Black Panther himself, T'Challa knows that he has long before his father leaves the throne to him, so he takes care of his family.
It had taken tragedy for he and Peter to bond, but he would not give up the smile on his son's face for anything. Though they are father and son, it does not stop Peter from pulling pranks on him, sometimes with the help of Shuri when she visits.
As Tony watches his husband be pranked by Peter and Shuri, he smiles as he puts a hand on his flat stomach, that will soon grow with child as the months progress. He wonders if his husband will faint when he tells him that he's pregnant, and cannot wait to see Peter's happy face as he tells him. After all he has been begging for a sibling
Life is good, and he couldn't ask for any better.
As he walks into the kitchen he catches a glimpse of the television, they spoke of strange happenings in New Mexico.