Charlotte's body disappears, Daniel says they're in the 1970s for good

Sawyer, Juliet, Miles and Jin find Daniel still kneeling on the ground where Charlotte's body was. Daniel is mumbling to himself and then tells Juliet "I'm not going to do it. I'm not going to tell her." Presumably, he means that he's not going to tell Charlotte in the past as a child that she will die if she comes back to the island. Daniel tells Juliet that Charlotte died and that her body disappeared during one of the last flashes. He says that she moved on but they stayed and they're not moving through time anymore. He then says that "Whenever we are now, we're here for good."

Are they really stuck in 1974 and onward for good? Can Daniel change what happens by not telling Charlotte that she will die if she comes back to the island?