well he wasnt being sexist-as he said, if she already had to have help in a fight it just proves she isnt ready to be in a real situation where fighting might be required he is trying to save her from potentially getting really hurt since they cant babysit her, and if she tries and fails she could get more hurt than the situation would call for
you claiming the character to be sexist because he doesnt want her to go and the artist not liking to draw girls
is 2 different things >___> just saying.
its fine to try to encourage the artist but saying one of the characters is being sexist in a classic comic-book-moment of wanting her to stay out of it thus trying to get him to make the girl character go just so he draws girls more, isnt how it is done. he is drawing girls more already to try to improve since he claims he isnt too good at them, a more positive nudge would be helpful id think.