Australian aboriginals have a very high rate of problem drinking, but is jailing them if they don't go for rehabilitation a good solution?

If rehabilitation were a reliable treatment, perhaps no one would refuse it. But as far as I know, for alcoholics to stay sober requires a deep commitment. The threat of jail can make someone go to an activity, but can't give someone that kind of commitment. So I don't see how this can achieve its goal.

There is surely a relationship between the high consumption of alcohol and the way aboriginals were kicked off their land and continue to be downtrodden. Changing that may be the only way to correct this (though it will take decades).