I read the series Armand as, once Louis has destroyed the coven despite their (including Armand) efforts to eliminate him, deciding that Louis is the one he needed as his anchor and thus taking credit for trying to save him. I tend to think that it was Lestat that dug Louis out of the coffin of stones and revived him. But I'm probably wrong.

You do make an excellent point that the series is stupendously incurious about certain themes. Produced in a different time and place it would be a very different series of course.