So much great advice has already been given
I will add my prayers and a wish for you to find peace from this nightmare....
I too am a mom and I too let my son come home too many times...
finally (when I was ready) I drove him to a shelter instead....that was the beginning of his recovery (2 years next month!!)
he is clean and living in a sober house.....one day at a time
please know that you are not alone
many have walked and continue to walk the path you are on
we walk together