What is the ruling on allowing children to study in non-Islamic schools in Canada, which involve teaching music and the belief that Jesus is the Son of God, especially when they are compelled to do so and their parents cannot afford the expensive Islamic schools? Are the parents sinful for this?

It is forbidden to listen to and study music. It is also forbidden to listen to disbelief, affirm it, and remain silent about it, based on the Almighty's saying: (And He has already sent down to you in the Book that when you hear the verses of Allah disbelieved in and ridiculed, then do not sit with them until they enter into another conversation. Indeed, you would then be like them. Indeed, Allah will gather the hypocrites and disbelievers in Hell all together) [An-Nisa: 140]. This includes a student listening to what Christians affirm about Jesus, peace be upon him. Children must be kept away from attending lectures that include disbelief or music. If this is not possible in a particular school, then they should search for another school, or resort to online and homeschooling. The interest of preserving religion takes precedence over every other interest, just as residing in lands of disbelief is not permissible unless one is able to openly practice their religion.