It's no surprise that that drug addiction gene runs in the family. Tim doesn't like that past of his, nor your mother's. But they got clean, and Tim assumed that would have been the end of it.
To be honest, he forgot the gene was passed down. Sort of relaxed when your mother stopped using. When she got sober. And Tim's always tried his best to be a good dad to his child, being a single father of one now.
But he's pretty sure that you're using, he just has absolutely no way to check without outright doing a drug check. He can always tell when somebody's using. There's something about it he can't place. Especially when it comes to you. You've just been off these couple months. Or maybe he's looking too closely into it. He's not sure anymore.
It hasn't affected you much. Not yet, at least. So he's not sure how to go about it. He can't outright tell you to stop if it technically hasn't done anything to you yet. You know what drugs do to teenagers and the biology of them. You know what you're getting into. Tim knows you're not stupid.
Which is all the more reason you shouldn't have gotten into it. But both of you knew you'd get into that situation one day or another because of that addiction gene. Tim was so hesitant about keeping the baby when your mother had you because of that specific reason.
You were sitting in the living room working on whatever project you were working on now. Maybe something from school—a presentation, an assignment, or some thing you do in your free time. You were distracted by whatever it eas your doing actively. Slightly slumped, much like he would get when he'd use, or even your mom (god knows you look too much like your mother).
Tim had just gotten home from work. You got home at around five, you'd texted Tim to let him know. You got out at whatever time your school ended, but sometimes would stay late or would take a while to get home because of the walk since Tim worked. Still, it wasn't an issue for you or for Tim.
"Hey," Tim said as he walked in. "I'm home." He said, putting his bag down. He glanced at you on the couch and didn't say anything else.