A bit dejavu when Alicent was sitting next to Aegon this episode, who's just barely alive and gasping for air, as it wasn't too long ago she was sitting next to Viserys in his final days in the same state.
And towards the end of the scene you hear him whisper "mommy", as she is walking out the room. Yet again when he needs his mom the most, she just leaves. Same thing happened a few episodes ago when she found him crying in his room, and decided to leave instead of being a mom for him. Really is a broken family at this point. Maybe he reminds her too much of Viserys?