Yes the lead arm needs work. It needs to stay up in the shoulder line like the clips posted.
https://youtu.be/-7295jQaoAwIn terms of drills one thing which might help is to have her get into her loaded hitting position and then give her the command to hit right from that position by turning the barrel.
There was a time the analysis skills on this website were better.
Ignore the GIF ... there is too much missing. Don't have time to make a GIF. Go back to the original video. Focus on the early (pre-swing) upper body movement forward.
The notion of swinging should not be to get on top of your front leg and stand up.
Ignore the GIF ... there is too much missing. Don't have time to make a GIF.