Substance abuse is not allowed at shelters.  Rehabbing or getting "clean" at the shelter would likely ruin the experience for the others actively trying to re-enter society.  Save your compassion for those making the effort (those in shelters).

One possible solution is for the state to create homeless rehab/detention facilities, for  voluntary and involuntary (i.e., assigned through mobile or district courts) extended stays.  This IMHO would significantly deter mainland homeless chronics from moving here knowing they couldn't use their drug of choice freely while having Hawaii residents enable their lifestyle.  

Then the Housing First apartments can go toward those who completed the rehab program or local needy families instead of single mainland transplants.

What has AUW done with the tens of millions so far?  Nothing meaningful, as it's not in their best interest to resolve the issue from a financial standpoint.  The worse the homeless problem gets, the more money AUW receives.