Some of these show a misunderstanding about what's happening. The reason that they gave him for kicking him out was true. It wasn't that they lied, it's that because of the reasons they gave, she is worried about him dying. The party's real reason was what was stated. Her specific reason is the party's plus fear of him dying. She shouldn't be telling him that part either before or after he has a breakthrough.
You're misreading it, which is odd because it's pretty obvious. Her fundamental presentation in kicking him out is that she doesn't care about him at all, and is kicking him out because he's useless and is holding them back. Then as soon as he leaves, she reveals that she does care about him and the real reason for kicking him out is that she doesn't want him to die. And it's confirmed again as she wander around town and listens to comments from townfolks.
"All of us have decided to remove you from the party." That was a lie. She was the one who decided it. Elf was fine with that, but Dale voiced an objection. Even if they had both agreed, the impetus for the decision was hers, not the group's.
"You are just holding me back" Another lie. She knows perfectly well that his enchantment magic is important to her performance. Now, she
could have argued that his magic, while useful, is like a crutch that she needs to live without, but that's not what she said.
The author's pretense here is to first have her present as a bad guy, then turn around and "show" that she's not a bad guy because she kicked Est because she was concerned for him. But this pretense is absurd and contrived.
Alternatively the author could have presented her as not caring about Est at all -- in which case the reaction after Est left would have been relief all around. ("Finally rid of the deadweight!" "Yeah!" "Whew!") But of course, in that case, they're revealed as assholes, and most of the audience would bail.
Her specific reason is the party's plus fear of him dying. She shouldn't be telling him that part either before or after he has a breakthrough.
That makes no sense to me. It's the reverse. If the truth is "I care about you and don't want you to die," then obviously she should tell him.
This is basic friendship. You have a buddy, you go on a joint venture with him, but it doesn't work. In that case, discuss it with him in private, make clear that though the venture isn't working, you don't want to lose them as a friend, and continue on as friends, but not business partners. What freaking lunatic thinks that the best way to handle it is to treat him like shit, claim you don't care about him, and toss him into the street?