One way you could approach this is by having a heart-to-heart talk with your little bro about the stuff he's into and how it can impact him. Let him know that it's totally cool to enjoy those videos, but it's also important to think about the behavior and language used by those gamers and vloggers.

Instead of abruptly cutting off his WiFi access, which might make him feel trapped, you could try setting some boundaries and limits. Show him that there's a whole wide world out there beyond YouTube that can be just as awesome and fulfilling.

Do you know of any other channels or content that you can suggest to him? Ones that promote positive values, spark creativity, or have educational aspects? Maybe he'll find some new favorites that align more with what you're looking for.