I can't imagine Lee dying, What if Clementine's parents are really gone.
Lee would be the only person left she has.
Although what if only Her mom or Father is left.
It depends actually we'll have to see at the end of Episode 5.
Most likely Lee may still be alive, but for a new character that would be hard to see, considering we haven't seen more characters.
A new character for Season 2 i would think if Clem's father is still alive it would be him.
(I'm not really a walking dead fan, I've only been playing the game.)