Great question! If your son is LGBTQ+, you found a great place to ask this question. Meta (who runs Facebook and Instagram) has an LGBTQ+ Safety Center full of resources and tools to help with keeping your child safe online.
If your son is experiencing cyberbullying, make sure he feels comfortable and safe talking to you about it. You can also work tother with your son on how to navigate or avoid the spaces online where it’s happening. The Family Online Safety Institute may also have good resources for you to explore.