Abortion is morally wrong

[Angrboda]

But what about the child's right to not have his mind clouded with fear of hell (which may be argued to be abuse, by the way) and rejection of modern science?

There's no such right. You made up an outlandish "right" to condemn an exercise of conscience that you dislike.

A non-religious example:

A father requests his children that, if he should ever end up having an incurable and chronically painful disease in the future, that he be allowed to undergo euthanasia.

Years later, it happens. The father is struck with such a disease. But neither the children nor the doctors in the area want to give what he asked for because of conscience. Even though the father desperately wants his life to end.

Which right to support now?

I don't think you know what a right is. If the father has a right of euthanasia and living will, he does not have any right to force others to facilitate the exercise of his right (with possible exception of explicit duties on doctors).

You're making up absurd examples that involve made-up rights. If you can't come up with a legitimate example using actual rights, then I'd say you've lost this argument.