There is an old saying, "you made your bed, now lie in it".
Until he realizes the full consequences of his choices, he has no reason to consider an alternative. Consider it a gift to allow him the dignity to do so.
One of the most challenging things about addiction, for me, is detachment, separating my own well being from that of my daughter's choices, regardless of what those choices are, good and not so good.
It is not possible to be embarassed for something you did not cause, cannot control or cure.
Takle the focus off your son and let him deal with the consequences of his choices. Sleeping in a homeless shelter is a good start.