What is the ruling on investing in a private school that teaches music and drawing, and it is likely that Christian students who study their religion will enroll in it, with some mixing, knowing that it is financially difficult to withdraw from the project?

Listening to and teaching music is forbidden except out of necessity and with controls. Drawing animate beings for children is permissible. Pictures of animate beings for adults are forbidden unless they are incomplete or lack features. As for teaching the Christian religion, it is a great evil and is not permissible under any circumstances. The solution is to establish a private Islamic school.