Men and women that are not romantically involved are often said to be in a "platonic" relationship
He should!!
No, it is not.
Because of the environment they live in.
It is absolutely normal
some relationships are called dysfunctional because of all of the ups and downs that happen
Peidophiliasm
Sure, you can have a nonsexual relationship. I don't see any reason why not. You can't have sex until she's 17, but it's not illegal to hang out with someone.
Inlove
Sociometry
yes. if the teacher interferes with the custody of the parent or guardian.
Yes, it's possible, if you want to work hard and keep it a nonsexual relationship then you can, if your partner wants to have a sexual relationship and you don't or your uncomfortable, ect. let them know. Hopefully they'll understand. Good luck!