So i always knew my parents smoked, never really brought it up with them and they never really bothered me when i came home baked off my ass smelling like bud. Then my first semester of college I was done with class early before columbus day break and decided i would just drop in at the house a day before they thought i was gunna be there. I get in the house and my mom is blazing a joint right on the couch watching tv, at first she thought it was gunna be really wierd but i just kinda sat down next to her took the J hit it once and passed it back like it was no big deal. i havent smoked with them since basically beause they always smoke in the afternoon and im always either at work or chillin with friends but its not wierd at all.
I wouldnt approch your parents about it or anything, chances are your dad will just kinda let you do your thing and if the opportunity ever comes up im sure they will eventually smoke with you