What is the ruling on girls (adults and non-adults) attending musical wedding parties accompanied by their grandmother, and does sin fall upon the mother if they go despite her refusal?

Adult girls must be prevented from going to weddings and parties that include forbidden things like singing and mixing, and the mother must prevent them from doing so, otherwise, she shares in their sin. The grandmother must also be admonished and advised not to go to such forbidden things, and care should be taken to choose righteous companions for them.