Oh; this again.
The Natives do not actually drink significantly more than the White people living in the Far West; on this much I can assure you. I guess having the money to drink a dozen Coors instead of eight Hurricanes does have a real effect on one's health.
My own advise to the tribal government would be to simply legalize alcohol on the reserve and than use the tax money to fund health/addiction care. But it isn't my call.