Is it permissible or forbidden to use money allocated for university expenses in a business venture?

Your friend's statement to his father, claiming he needed a sum for university that he did not in fact need, is a lie. He must repent and inform his father of the truth. If his father forgives him the excess amount, then there is no harm; otherwise, he is obligated to return it. As for you, it is impermissible for you to take your father's money without his permission. Since you have done so, you must return it as soon as possible, along with repentance and seeking forgiveness. You are not required to inform your father if you fear negative consequences. Your business project is permissible as long as you have not invested the stolen money in it.