I wouldn't tolerate it. My kids wouldn't do that and I wouldn't accept disrespect from somebody I am trying to help. This type of kid needs discipline and although you aren't going to change what they do when they leave you, you can demand respectful interactions when they are with you. When coaching a team, you can't let the inmates run the assylum. We don't tolerate non sense between teammates, with fans or players from other teams. Somewhat different but the theme is the same.