He read my message and didn't reply. What does it mean?

The read receipt is there; the answer is not. That tells you the app marked the message as read, but it cannot tell you why no reply followed. The useful distinction is whether your message needed an answer or simply closed the conversation.

If a question or plan is still waiting, a direct follow-up can name what remains unresolved. The time you need an answer by can be your own planning boundary, without turning his delay into a test of his feelings.