I mean, it's not like he never told them. He always says that other vampires were vicious. What he didn't tell them is that they're safest with him.. The other vampires will never come after them if they stay with him.
While it prolly would sound like another lie.... He should have made them stronger and taught them how to fight.
But to all his faults....Lestat, Louis & Claudia had a relationship that lasted longer than most vampire covens....
Most make 20-30 years together before splitting up. I forget what book brought it up, but it was mentioned once that is very rare for a coven to make it more than 50 years.... If I'm not mistaken, they made 65 in the books.
At the end of episode 6
It looks like they had 10 years before Claudia, and about 20 with her