What is the ruling of the Sharia concerning a son who disobeys his parents, and what should be done with a son who is heedless of this?

Disobeying parents is one of the greatest major sins. You must strive to guide your brother, remind him, advise him, and encourage him to listen to beneficial tapes, keep company with righteous people, and associate with mosques. You can seek the help of committed brothers to establish relationships with him and ask him to perform Hajj with you to be your mahram, for "the Sacred House was made by Allah a guidance for the 'alamin (worlds)." Allah, the Almighty, says: "Indeed, the first House [of worship] established for mankind was that at Bakkah - blessed and a guidance for the worlds."