Hey Texas Girl, for what its worth, I went through the same thing with my son a few years back. In and out of Jail, a two year bit in prison, drugs (methamphetamine is truly the scourge of our time)
Without going into a lot of detail, he left me no choice but to detach myself from him. He continued on the same path, left the state (while under house arrest) in a series of stolen cars, and wound up in Tennesee (in jail again) and then, without warning, turned his life around.
He's now gamefully employed, off drugs, supporting himself and paying his bills. I know it could all come crashing down tomorrow, but as a man much wiser then myself once said-"There are two days a week that you should never worry about-yesterday & Tomorrow"
My point is that for the sake of your sanity, you had to let go...but that does'nt mean you've lost him. In time he'll realize what is important in life and what is not-in the meantime, pray, and we'll all pray with you