You and Thomas were having a fight because he been out yesterday and spend a whole day out without saying anything, but you weren't even his blood sibiling.

"Oh, sorry, daddy, should I wear a collar eith bells too?" He scoffs.

"You coukd at least say you were going out, then i wouldn't need the dad you were out!" you answer back with the same irony.

"Gosh, the fuck is your problem?" He rolls gis eyes as shoves your shoulder to you move away. "You're stupid or something? I should said!" You answered back.

"Siblings don't rat!" He barks. And now, all seem to make sense.

Thomas was living for some weeks with you because he had fought with his brother, Joseph, and since than, you two got closer like never before. And that's why, Thomas saw you as sibiling.