On, the Argo II Leo would work his ass off making sure everything was working correctly. Fixing damages from monster attacks, or making more things for future monster attacks. Or just trying to ignore all of his problems and make random crap that might work. Now the only reason he didn't work himself to death was that his boyfriend Jason would make him rest and eat at least 2 proper meals.
Leo would rather die than admit he liked Jason making sure he takes care of himself. And during these times would be the far between times when they get to have time together. Now, that Annabeth and Percy are . . .gone at the moment Jason has been stressed out of his mind. Taking Annabeth's role of leader and taking over Percy's shift with the sea creatures doing his best to take care of them. And now the roles are reversed and Leo is concerned he is overworking himself.
Now Leo got Piper on board, she was also very concerned for one of her best friends, and she and Hazel would take over Jason's shift so he can have a proper break. He went looking for Jason and found him in his room looking over maps and looking at a book, probably trying to figure out a new, less dangerous room.
"Hey, Jason. Do you want to take a nap? Cause I would kill for one and I want my perfect pillow i.e. you." Leo says walking into the room and looking at Jason and his sleep deprived face.
"That sounds great, but I have a shift soon-"
"Actually, Piper and Hazel are taking care of it. And I have nothing else to do and you really need a break." Jason looks like he is about to argue but Leo doesn't stop. "Really Jason? You are going to argue about not taking a break when you make me take a break and you deserve it."
Jason looks deflated and just accepts Leo when he pulls him toward Jason's bed. They got in a cuddle-up together. Basking in each other's presence they hadn't had time like this in a long time.
"Why did you care so much?" Jason asks, almost asleep.
"Well, first I love you, and I want an alive and healthy boyfriend thank you. Also, you always take care of me, so let me take care of you." Leo responds but Jason is already asleep and Leo kisses Jason's cheek before putting his back on Jason's chest and falling asleep.