Is it obligatory for a father to command his adult son to study academic subjects, and what are the repercussions for the father if his son does not study or gets low grades?

The mature, sane son is responsible for himself, so he is not subject to custody. However, the father is requested to advise his mature son and guide him to what is in his best interest, and to command him with what benefits him in his religion and his worldly life; for advice is a right of a Muslim over his Muslim brother. If the son falls short in his studies after his father's advice, there is no blame upon the father.