Always figured she based him on David Talbot-Rice, the posh English historian whose books sat beside hers in public libraries en.m.wikipedia.org/wiki/David_T...
I'm slightly freaked out by the TV show Lestat; I did not expect him to be so... unhinged. And cold. But then I think back to the books, and I can see how they got there.
Bit of a spoiler, but a lot of it comes down to how Louis was describing him. Once he gets out from under Armand, he reunites with Lestat, and he's much more kind and human character.
Basically, reality is our perception, and the perception is skewed.
Not a spoiler to me - I read them all back in the old days when a paperback cost less than lunch.
I still never saw him quite as unhinged as the tv show portrays.