Hi, I'm think you should let it go and next time S is out with his dad then make it insanely clear before he takes him what time he's expected back. Can you also let S know what time his dad is expected to bring him home?
It's so tempting to get into the convo with your H but where will it get you? I think to respond might be a cheeseless tunnel.
Jen *The more anger towards the past you carry in your heart, the less capable you are of loving in the present*