There is plenty of help to be had but only if the person accepts it. There is rehab, school interventions, community interventions, psychiatric help, psychiatric medications etc. Most of us have offered all to our kids. That in my opinion is practical advice.
If they won't accept the help then nothing will work. It takes an effort. We can not help somebody not willing to try or to change. I'm sure plenty are helped by these resources but their parents don't need to come to this forum.