I have seen Dr. Drew a few times here and there and he seems to have decent knowledge about addictions.
Now IMO there is a HUGE flaw in trying to get clean/sober on a reality TV show. The public performance aspect is completely contradictory to the (supposed) goal. In a pristine world, there would be no such show. All professionals with integrity would refuse to participate.
However most people checking into the Dr. Drew show aren't particularly serious about getting clean and sober and doing that is better than nothing. Sometimes doing something for the wrong reason can still work out. It might at least plant a seed if they ever do get serious.
And if it wasn't Dr. Drew, it would just be someone else.