Just finished watching 13 reasons why and it's disturbing.....What can we do as parents to reach out?

So I've been binge watching '13 reasons why' and finished the last of season 2 today. The show has very much disturbed my mind seeing how helpless the whole situation is.

I have kids of my own and they are still very young. What can I do today to let them know that I will be there for them tomorrow when they are teenagers and they experience stuff and emotions they have never experienced before? How do I build the trust?

Just yesterday, my seven year old and friend were apparently lightly punished in school for talking while the school head was talking. He refused to open up because it was embarrassing to him. It makes me wonder how'd I get him to talk much later if he doesn't even want to now.

Also, there's this neighbour's kid who comes from a single parent family. He's an only child and he follows us home. He has been using swear words and I advise him not to. He said he heard these words from a friend from school. I'm not sure how involved I should get in this. Do I tell his dad about it or his grandma who lives with them? He gets scared when I mention his grandma/dad for they'd scold him if they find out about it.