Annoyingly, there is actually a grain of truth in this. The 12 step system (AA and all its related groups) for dealing with addiction and related disorders is based on the person referencing a 'higher power'. This higher power can be anything (nature or fate for instance) but for many westerners it is naturally the christian god as that is what they are familiar with. Basically (very basically) the theory is that the underlying problem giving rise to the addictive behaviour (ie why they drink or eat or whatever to escape reality) is related to childhood experiences, especially with family or adult authority figures, in particular not being unconditionally loved as a child should be. The 'higher power' takes the place of the loving parents (I think this has alot to do with the popularity of religion generally, even for healthy people) and allows them to fill the gap and thus move on with life in a more healthy way.
Basically, for a very ill individual, the comfort and more importantly the strength gained by thinking a loving entity is watching over/protecting/guiding them can make all the difference between recovery and topping yourself. I have seen this work, it is extreamly effective.
That said, it aint Jesus what does it -the 'higher power' can be anything and anything works just as well as anything else. Also, it doesnt actually 'heal' issues - just puts in place a supportive framework within which recovery is, for many, more of a possiblity.