Is it enough to advise someone on stopping with a sin without telling them evidences?

Asking this because a few months ago i was watching/a fan of a tv show which i now realize is haram (few curse words, some inappropiate scenes). I'm saying “realize” because i used to watch it (and stopped Alhamdulillah) but during that period i told my cousins to watch it, but they didn't seem to care. Then one day my cousin apparently decides to watch it and likes it. Now i fear his sins are on me. My question is: would it be enough if i just tell them to stop with the sin without telling him it is actually haram?