This is incredibly common, especially in middle and high school. Many children tolerate discomfort to preserve belonging. They may fear that setting boundaries will make them isolated.
You can help by validating that fear while still reinforcing their right to feel safe. You might say, “I get why you don’t want to rock the boat. At the same time, real friendships leave room for boundaries. We can think together about what feels safest for you.”
Sometimes the goal is not confrontation but distance, changing the subject, or finding allies.
Simple, calm language works best. Children do not need long explanations. Phrases like, “That’s not funny to me,” or “Can we stop joking about that?” are often enough.
If a friend reacts poorly, that gives important information. A relationship that cannot tolerate respectful boundaries may not be as safe as it feels.